I think relating longevity to burn speed could only be done as overgeneralizations... Burn disc at x speed. Test C1/C2 (CD) or PIE/PIF (DVD). Burn same brand at y speed. Test. If x errors are lower than y, burn at speed x. Done!
It's generally accepted, at least with DVDs, that most people will have the most luck at the rated speed. If you buy a brand new pack of 16x DVDs, your drive probably won't let you slow down to the baseline 1x (-R) or 2.4x (+R), and burning at the slowest speed available may very well produce more errors than a faster one. So much of it is drive and disc dependent, the only way to figure it out is to do some tests and see what works for you.