What FPS should I use for smooth game logic when tweening

I am using tweening to get a constant rate, but just how many updates should I do to the game logic per second, is there a standard (15 FPS, 30, 60?)

Cheers

I use between 20 and 30.

Sounds like a good suggestion, but if you want people with old systems to play your game, you better make your game skip a frame whenever the computer can't keep up.

Rob, I've settled on 30, which is ok (no-one's complained yet) and it allows me to have lots of entities and animated characters!