Everybody is different in how they handle bank rolls & comfort levels. I only play with "spare" cash presently, as I'm trying to build up my BR slowly. I play at a wide range of stakes, depending on how the cards are falling. Good & bad cards seem to run in streaks for me. So I usually start at a lower level stake & if things feel good I'll step up a table or 2. I also play better a lil bit "scared"!....LOL. I think it has to do with focus. At lower limits, I tend to get bored. If the cards are going good, step up, if they're not, quit for awhile if you start to lose focus. Seems to be working well for me so far.

Good luck!