Inspiration is a KEY component to encouraging roleplaying in 5e. It is one of the elements that really changes up the game by directly rewarding roleplaying without using XP as the reward.
The assumption in the game is that PCs earn inspiration whenever they roleplay their character’s Flaws, Bonds, Ideals, and/or Traits. A typical player should be able to trigger this at least 3-6 times in a session.
Inspiration is a binary thing. Either you have it or you don’t. You can’t have more than one.
You can spend inspiration in two ways
1. You can give it to someone else for being awesome. So if Fred pulls off an awesome stunt, you can throw Fred your inspiration.
2. You can spend it to gain advantage on any d20 roll.
I recommend spending it quickly, so you’ll be able to get it again next time you roleplay a flaw, trait, bond or flaw.
The trick to prevent players from hoarding their inspiration (so they’ll have it for that crucial death save or saving throw against dragon’s breath) is to hand out inspiration often. My experience is the only thing players hate more than the thought of not having a resource, is the thought of wasting it. Every time you give them inspiration when they already have it has them feeling like they are “wasting” an inspiration.
Once they know there’s a good flow of inspiration, they start spending, and the game’s “inspiration economy” steps into action. The big roleplayers will start handing off their inspiration to the players who don’t roleplay as actively in order to make room for their next one. Hand them out like candy. The more often you hand them out, the more often players will start using them.
I use nice big fantasy coins to represent inspiration, so they are clearly visible and easy to remember, and make the “economy” aspect more tactile.
Sean Goodison (@HighScoreKid) introduced me to a system from @is3rith that makes the system even easier AND better by handing the whole economy over to the PCs.
Each PC is in charge of giving themselves inspiration when they roleplay their Flaw / Ideal / Trait / Bond. The big difference is that they can’t trigger any one of these items more than once per session.
This gives a cap of 4 inspiration per session which is about perfect for a 4 hour game session for keeping the whole flow of inspiration going; and it means the DM doesn’t have to track 16-24 different inspiration triggers.