Every once in a while I'll ask, or go to Inferno, or somebody will offer...
When I get a set that feels right I use it everywhere and make adjustments for the track. When I say feels right, I mean slightly oversteering from neutral, good on the curbs, and recoverable. The latter being my highest priority. I have to have a car that can come back from my mistakes fairly easily. In the end I do adjust cambers, spring rates, ride heights, dampers, gearing and wings quite a lot. Gearing and wings will go a long way for a car that feels good. If I find I'm struggling for time I will start the search anew, trying to find the next best set.
Overall though it's about comfort, anticipation, and the ability to go 80 laps from start to finish.