My personal limit has been to stick with one camera of each format that I'm willing to do darkroom work with. So that leaves me with a 35mm digital, a 35mm film, a 120 and a 4x5. I've been fortunate that each one showed up at a time when I was ready for it

The only exception is a "needs work" graflex from WW2 that I took on as one might take on a stray dog that needs a little kibble and a blanket of its own to turn its life around.