How do you use experience points in your D&D or Pathfinder games? Do you use them as written, or do you houserule them somewhat?

There are a few different approaches to XP. I've used all of them in my time.
  • Individual XP. I expect this is the most common usage. Each players tracks their XP separately, and XP awards can vary from character to character depending on what they do in that game session. With this approach, characters can level up at different times. This is pretty much the default "rules as written" approach.
  • Group XP. All XP is shared equally amongst the group. All characters therefore level up at the same time (unless you're using an older edition of D&D which has different XP tables for each class). The assumption here is that, although in some sessions some characters may do more than others, in other sessions it balances out. Plus, they're all part of it really, even if it's just healing each other afterwards or being involved in the planning, or contributing to the resources used.
  • No XP. Some DMs like to just tell the players when to level up. This helps ensure that they are the right level for the next adventure; this is probaby used most frequently when playing a pre-written adventure path style campaign where having the characters at the wrong level for any given adventure could mean extra work for a time-pressed DM.
On top of this, we have the issue of absent players. Some groups will allow an absent player to gain XP; others will not. Some groups may allow the absent player to gain half XP, or might determine it based on the reason for absence - "I can't be bothered to drive over tonight" being different to "I was just in a car wreck and am currently lying in a hospital bed".

We also have the concept of effort-based XP. Some DMs like to give XP to players who act in a certain way; that's most frequently evidenced in "roleplaying" awards - a player who roleplays particularly well in a given scene may get a bonus of 200 XP, for example. A player who provides a well-written character background may get XP for it, or one who provides an appropriate miniature. These XP awards are all geared towards the DM conditioning the players into playing in a certain way, and making a certain level of effort.

Then, of course, we have the variance in timing. Do you give XP immediately? Do you give XP at the end of a session? Do you give XP at certain junctures in an adventure? And, depending on these factors, when may a character level up? Between sessions, between adventures, in mid-session?

Some older editions of D&D put some heavy brakes on XP. In addition to having different XP progression tables for each class, often gold and time would have to be spent "training" in between levels; later editions assumed that training happened constantly and in the background and didn't need to be specifically spelled out.

Myself, personally, I've tried most of these variations. A long time ago, I'd even make each player justify why they should get bonus XP at the end of each session. These days I prefer the simplicity of group XP, but I recognise the fun of tracking it individually. I don't think this is something that needs to be hard-coded into the rules system; each group will do it differently anyway.

One little thing we did with WotBS was to allow a party to have NPCs (especially useful in a smaller group) which provided needed resources (healing, thievery, or what-have-you). The players would control the NPC during combat, and the DM would do so out of combat. The NPC would not take a share of the XP unless he or she became bloodied (this was a 4E game) - this led to an interesting dynamic where players used the NPCs sparingly and tried to protect them. The NPC, of course, simply leveled up automatically between adventures.

So what about you? How do you award XP? How often do you award it? What do you award it for? What do you do about absent players? And when do you allow characters to level up?