I've just taken a look at flylady and while the tone makes me want to claw my eyes out, the routines seem sound, and a lot like the things that I'd been brought up doing, and have had to institute as houserules here, as DH was brought up by hoarding, messy, chaotic, dirty people, who frankly made him embarrassed and confused and chaotic himself. Things like clean out the sink and wipe down the counters before you go to bed (waking up to a clean kitchen starts the day in a calm manner, and you've always got a clean mug for coffee), emptying the dishwasher on a morning while you wait for the kettle to boil, never leave a room empty handed, etc. Habits are good cos then you're doing maintenance work without stopping to think about it. Usually as a feminist I think stopping to think about things is good, but if I stopped to think about how boring it is having to feed myself, and why should I have to do such a thing three times a day, I'd starve to death. Ditto cleaning/tidying.
We do kitchen, bathroom, and hoover all floors once a week, or every two weeks if we have a really busy weekend (then we do a sort of swish and swipe). I used to be a hoarder, but found a transatlantic move with only 2 suitcases good for that.
Habits can help, SGB but I think working out why you're hoarding/developing tactics to help you release things will be more important for effecting real change. You're right - bits of string do 'come in' handy sometimes, but what if you had a ball of string that you kept in it's own place in a cupboard, and then if you were ever tempted to keep a bit of string you could say to yourself "I have enough of that."
From what I've seen of hoarders they either have a great fear of scarcity or a great guilt about 'wasting' things. You need to change your brain about having enough of things, and it being a wonderful act to free things to go to other places.
Freecycle is great for that. If you're keeping something cos it might come in, advertise it on freecycle and someone who wants or needs it NOW will come and get it. So it does 'come in' - just NOW instead of 'someday', and for someone else instead of you. But that's fine! Because you have enough.