I'll start off by saying that I've read the stickies on yeast washing and slanting--I've been washing/harvesting for a couple of years now and intend to start slanting, but this question relates specifically to harvested yeast.
I've been fairly unscrupulous in the past and have ended up with some rather interesting brews as a result, which I can best attribute to harvested yeast of later (or, horrors!) contaminated generations. Obviously, fixing contamination issues is easy, and is merely a matter of altering packaging procedures. I'm not horribly worried about THAT, as I've only ever contaminated one batch and that had nothing to do with yeast.
So, my question. For those who harvest yeast, are you concerned about things like generations, gravities, and the like? IE, if I harvest yeast from a 1.060 batch, I've read things in regards to only pitching that yeast into a batch of higher gravity. Additionally, have read that one should only harvest for about 2 to 3 generations. Of course, use of a starter should be assumed, and size/length of starter related to OG....
Thoughts? Basically looking for general guidelines for utilization of harvested yeast. Thanks!