How Long Should a Game Be?

I've participated in games that have run for vastly different time periods.  Some games I've been in or run have been epic in scale.  Some have been so fast and intense that they've been a single memorable blip.  I've been in games that ran too long, games that ended too soon, games that were unappreciated in their time, games that seemed great in the moment but were forgotten as soon as they wrapped.
Along the way, I have developed some opinions on how long a game should be.
Essentially, most of my answers are going to be somewhat vague, because different games require different things, but most of my answers will be phrased along the same lines.  What should make a game longer and what should make a game shorter.

How long should a game be?
The basic answer is simple: long enough to tell the story.  But that isn't a firm answer.  There are stories that can unfold in three sessions and stories that take five years to tell.  Overall, a game will suffer if it is compacted too much or stretched too much.  A game that's too compacted will feel rushed and can be confusing too much detail in any one point, no time for processing.  A game that's too stretched may end up losing momentum or having players not see how things fit together.  How do you know how long the story takes?  That's a hard question.  I tend to break down stories into steps or dramatic beats.  In order for the neighboring kingdom to invade, they need to manufacture a casus belli, amass troops, move those troops to the border, seize the first line of defense, the second line of defense, find a way to break through the final line of defense and then seize the capital, install a puppet government and demobilize their army except for an occupational force.  So something as simple as an invasion has 9 steps to it.  Some of those might be combined, some might require more than one game, but having the steps of the process laid out can tell you that the story of the invasion of a kingdom is going to take at least 8-10 months.  Every story can be broken into parts, some big, some small.

Beyond just the story length answer are a number of other factors.

I think a LARP should be short enough to maintain a consistent central cast.  There should be people there at the beginning who see the end.  And while a little cast rotation can be a good thing in a healthy game(eliminating those who aren't interested, adding those who found out late), a game that can maintain the continuity of a central cast is generally better than one that can't.

A game should be short enough to avoid excessive power creep.  I've spoken about the perils of experience systems.  The longer games go on, the more power tends to become consolidated/imbalanced.  This isn't just an XP problem, it can be a plot access problem.  When the older players have lots of plot-centric influence they've built over chapters 1-4, those who start in act 5 may feel marginalized.

A game should be long enough for people to settle into their characters and factions.  In games where players create their own characters, there is generally a period of settling into the character.  In games with political factions, it takes time for groups to gel.  A game should be long enough to allow that process.  Some of this can be taken care of with pre-work, but pre-work is just that, work.  It's much more interesting to play out a massive internal factional schism than to simply talk about it.

A game should be short enough to avoid staff burnout.  It takes so much work to run a game that after a while, the staff can get very tired.  Very long projects can feel stifling, as staff members(who tend to be creative project types)want to move on to the next project rather than lingering on the current one.  This can be addressed by adding new staff, but that can dilute the central vision of the game.

A game should be short enough that every part serves a purpose.  Not every game should be plot heavy episode after plot heavy episode, but there should be a minimum of filler content.  Some sessions may be designed to be light on the eventfulness, a chance for people to explore facets of their characters or mix up the general patterns of the game.  Things like bottle episodes or tabula rasa type games can be great for resets.  IC event games like weddings or funerals or holiday celebrations can be fun in a game situation.

A game should be like an ideal gas, it should expand to fit its container.  Running games in many contexts means tailoring the game to the time constraints.  If you're running a game at a con, it should be a quick one shot, set up to develop and resolve within the time slot.  If you're running a game at school, it should be able to be set up and completed in a semester.  I've tailored timelines for games based on local weather patterns.

Overall, finding the right length for a game is a complicated process.  I've already stated my opinions on bounded storytelling, but this is a great time to reiterate that.  A game should have an end.  Endless games are shapeless and memorable not as a whole, but as parts.  If you're going to treat the game as a whole, you should think about the entire shape of it.

What is the Point of Experience (Points)?

What is the point of experience points?  Nearly every game uses them, or at least some variation on them(Karma, Advancement Points, etc.), but what is the actual point of them? And more importantly, are they appropriate for every situation? and do we use them to do too much?

What is Experience?
So, at its base level, experience is a marker of character advancement, a way of representing character change through accomplishment.  As the character achieves goals, they get better at what they do.  But it is something more than that.  Experience points are not just a manifestation of learning, they are a manifestation of story form and to a certain degree a relic of the story forms of early games.  Dungeons and Dragons and fantasy narratives in general are based around a certain unlikely hero story form.  In that sort of story, which draws heavily on traditions of fairy tales, fantasy stories and bildunsromans, the hero begins the story the victim of a villainy or lack and cannot right that villainy or liquidate that lack until they are stronger.
Experience points become the method to explain that strengthening process.  It shows how Conan the boy can become Conan the Barbarian(and slay Thulsa Doom).  It explains how Meriadoc Brandybuck can go from scrumper of apples to slayer of Witch Kings(and liberator of the Shire).  It explains how Rand al'Thor can...do whatever it is he does(I didn't actually read that book series).   Experience points started as a structure to allow for that kind of storytelling.

Variations on Experience Points
In other games, Experience has been adapted but rarely abandoned entirely.  The classic model of Dungeons and Dragons is the linear advancement model.  Experience points buy levels, which progress along upwards power curves.  Other games use point buy systems, where you get generic experience points that are spent to raise specific skills/powers/abilities, representing a manifestation of effort at self-improvement.  This system allows for more nuanced development, but can also lead to oddly unbalanced characters or incongruous advancement(I learned a lot during our fight with that Mummy, like how to better influence local politics).  Some games use targetted achievement systems, where using a specific skill makes it improve.
Games also vary how experience is gained.  The classic model of Dungeons and Dragons is killing things.  Other games use story advancement, achieving plot points or good role playing to earn experience points.  Many targetted achievement systems mark experience through breakthrough moments, where outstanding success marks an opportunity for improvement.  My personal favorite is Dungeon World, where you get experience points whenever you fail at something.
What all these have in common is that they all represent an upwards power curve.  Characters start weak and get stronger.  But that strength is more than just symbolic representation.

Experience as Influence on Narrative
More experience equals more power, and more power equals more influence on the narrative.  Ultimately, a change in power level allows the PC to do more things, to interact with parts of the world that were inaccessible before, to take on enemies that previously eluded them.  This is both good and bad.  For games where everyone advances together and is part of a single team/faction, this can generally add up to the world becoming more the playground of the PCs.
However, this breaks down when you get to games that have multiple groups competing for influence over the narrative.  While experience points are not the sole method of influencing game narratives, they are a part of the overall equation.  When there is a significant power differential between characters in a game, those that have a lot more power are able to exercise a lot more control over the narrative. In these cases, experience point differentials can be a significant problem, because there is very little as disengaging as feeling like you have no influence over the game.

Arguing Against XP
This is one of the reasons that I'm strongly opposed to the current system of experience points being used in most ongoing LARPs and why I think LARPs can take something from standard tabletop practice.
1. I don't believe in XP as an OOC reward system
Some people have more time than others.  Some people have access to more money than others.  Some people have skills that others lack.  Depending on the game, these can be turned directly into narrative influence by volunteering/buying things for the game/making objects for the game.  This disengages people who don't have access to the same resources but still want to participate.
2. I don't believe in an arbitrary universal starting point.
In the D&D games I've played, when you bring in a new character, that character's level is related to the level of the other characters in game.  It might be average level-1 or same as the lowest level character or experience equal to whoever in the party has the least, but almost nobody forces you to bring a level 1 character into a level 12 game, even if everyone else started at level 1 initially.  But in many LARPs I've been to, new characters start out at starting level even if there are characters in the game walking around with hundreds of XP.  I think that LARPs can learn from tabletops here, establishing XP floors that allow new characters to feel like they aren't completely behind.
3. I believe in XP caps

There is a point of diminishing returns on XP as a narrative instrument.  I run bounded games, games with pre-defined beginning and ending points, which regardless of system, puts a cap on the total amount of XP that can be earned.  But not everybody does this.  I have participated in many games that had been running for years, with characters earning experience points the entire time.  In so many cases, I heard players talking about how they didn't know what to spend their experience on, so they were learning irrelevant skills or becoming experts on obscure lore.  This does more than just unbalance a game.  This cheapens the idea of character.  One of the reasons that characters have different skill sets is that it provides a method of focus sharing.  When a character has reached the point where they can solve all problems on their own without help from other characters, then the game becomes not a group participatory exercise, but an exercise in narrative masturbation.  XP caps limit that.  By having a maximum amount of XP, a character can only specialize in so many things and situations that require multiple degrees of expertise thus require multiple characters.  

One Solution

So, for the Changeling the Lost game that I am about to wrap up, I used an experimental system of character advancement.  Rather than have an experience point system that depended on attendance at game, all characters were given a total number of advancements(24) based on the total number of games(24).  These advancements could be used to advance any aspect of the character, so long as there was narrative justification.  

Players could spend them at any point in between games, starting at the beginning of the game with all of them spent or starting late in the game with none of them spent.  This put an overall cap on potential power and allowed for a variety of starting points.  It simplified calculation and character sheet tracking and removed arguments about power differential based on XP.  

Was it perfect?  No.  There is still a power differential based on system knowledge.  There were people who engaged with the system much more than others.  There was some confusion over the timing of things and honestly, when I could no longer print character sheets out for free, we went to a much more system light approach.  But I think it's better than the alternative, maintaining the good parts of XP while avoiding many of the pitfalls that I've seen.