Well, I may be naive, but I don’t see any problems in burning as many media as wou like in a row. Of cause, the life of the burner will end one way or another, but if you spare the drive, it will become obsolete in a few years anyway. I haven’t bothered to find the MTBF (Mean time between failures) of the drive, but I expect it to be high.
Regarding the disc I am not aware of any negative effect involving the temperature of the disc at burn time - I cannot see any difference whether I burn in the winters (20Â°C) or in the summers (30Â°).
To sum it up - in my opinion, concentrate your concerns regarding temperature toward storing more than making the disc, although also in this case I expect all my high quality DVD’s to outlive the technology anyway…