Halfjack

In my current 5e game, I have some items that have soft limits on how often you can use them, in that each time you use them you make a con save or gain a level of exhaustion, and the dc increases as you use them more, and the dc resets when you finish a long rest without any exhaustion.

It's not a force though

they're epic level, they can probably handle it.

on the other hand, if they fight Szass Tam or Sul Khatesh...

Since like, the 70s

Iirc, it's a children's book about an elephant named Horton discovering a civilization of tiny creatures living on a planet the size of a speck of dust and protecting it from other animals.