Bingo!

'I think partly it's because I feel if I take them at this level of pain, they may not work when I "really" need them.'

The above was left as part of a comment by AJ. This is precisely my fear. I have already, 15 years ago, experienced trouble with a drug where one needed higher and higher doses for it to work and then stopping it altogether was a nightmare of withdrawal. I swore I'd never go thru that again. Already, one of my drugs, which I take infrequently, is no longer as effective as it was when I first took it. I say infrequently meaning once a week or less. If I can gain a tolerance to a drug just taking it like that, you can perhaps see why I am afraid to take my pain meds regularly. Also, my condition is progressive and I don't want to be left with no pain relief because my body is used to drugs OR have to have such high doses it leaves me in a stupor or dead.