Track it until it you get a good take for all sections, listen back to see what bars you need to punch/fly-in an alt take, when the whole song works you're done.
I've never really followed this "track a whole bunch of stuff, then wade through it later" philosophy. It's too much work. Track a quality take, fix the stuff that doesn't work, do a safety-take if you're feeling uneasy, then call it a day. I'm convinced that this comping-lust comes from studios wanting to decrease the efficiency of their workflow to make up for the increased-efficiency of working digitally. Gotta tag on the hours somewhere.