I hope that I don't someday regret writing this.

But, here's my guess.
And, It's ONLY for those of you who have a solid relationship with your neuro, or pain management psychiatrist. (Whomever is doing your prescribing, which, should be 1 person) naturally.

For instance,
Mr Bluffit has RSD / TOS and some discs, that all act up you know, some days are worse than others.
The doctor has him on a "cocktail", and one opiod, let's say Methadone, is used for pain relief.
Mr Bluffit is given 30 mg. / day. 10 mg each.
One morning, One afternoon, One evening/bedtime. "As required".

On a good day, what Mr Bluffit must do, is to take half a pill when possible. Or, skip one.
This allows him to build up a very small "stock" for "Breakthrough" pain.

I don't know the name for this, but, it has been told to me, by my own doctor's office, that I'm responsible for "saving for that rainy day", as they cannot prescribe for it.

Couldn't make more sense to me!

Some days I may be just "lazing" around. Naturally, I take less of the pain med!
We're Not machines, or cars, that must have our "tanks filled".
We can cut back when we're able, and have that half a pill or so, to use on a bad day, after we exerted ourselves, or the weather is bad, or, on and on.

I hope this might help.

pete
asb