that's like speed dating with cigars. Shame they can't roll a sample sized cigar.
I always make it at least half way before tossing one. I can't say I have ever had one redeem itself, but I have had some turn bitter for a few puffs near the end, just to smooth back out through the nub.

As far as relighting I used to do it when I was in the sandbox but I always cut an inch, purged and stored in an aluminum tube.
Sure they didn't taste great, but I don't remember them tasting that bad either. I haven't done it since, I just smoke an appropriate vitola and if surprise plans interrupt toss it, and start a new one later if I can.