I told my doc at my recent visit that a couple (maybe 3) times a month, I end up putting on a new patch at about 60 hours rather than 72. Depends if I've been exherting myself & pain spikes, or like you said, predisposing myself to higher temps, which will drain the patch quicker... He surprised me by giving me TWO extra patches this time! What a pleasant surprise .
It IS hard to make 10 patches last 30 days. Putting on a new patch 12 hrs early a couple times a month uses up one extra day.....if there are 31 days in the month, well that works against us....so it's very easy to fall short somewhere along the line, thus suffering w/d symptoms for a period of time.
Also by day 3, I begin to get pretty severe depression symptoms and anxiety. I just hate the fact that my life seems to revolve around these patches, but at the same time I'm very grateful to have this pain management.

At one point a couple years ago, I was prescribed for every 48 hours. Absolutely NO room for withdrawal symptoms in that case, which of course is very nice, but that's keeping a pretty heavy stream of fentanyl in the system....not to mention the extra cost.
You're right, it is a very individualized thing.