Falling behind on meds is the worst. I have my iPad with me all the time and set the Clock to play a song every 4 hours, day and night, which it will do until I tell it to stop some day in the future. When it goes off I make a lunge for the meds bottle and take it right then, with or without water. I learned early that if I put it off (i.e. I'll take the meds in a couple of minutes, just want to finish what I'm doing ...) I can't always remember if I actually took the pill or not ... or maybe I even forget to take it those couple-three minutes later. My short-term memory and focus have suffered a little bit with hydrocodone!
At one point I tried the "when I feel I need it" approach but discovered soon that it takes at least a half hour to kick in, and that half hour is horrible. Since it does seem to wear off at just about 4 hours, I'm letting the clock make all the decisions. "Stay ahead of the pain" is now my mantra.
Every few days I see if I can do half a dose, in order to start tapering down. So far, the answer from my body has been a definite "no."
Good luck CJ, and I hope you are one of the ones who finds it's easier than you expected!