Teenage son driving me mad

[HowManyTimesDoI]

So as my username says how many times do I have to repeat the same stuff before it sinks in and he gets it?

I don't think I'm asking much, I just want him when he takes his trousers off to have the legs both the same way so when I've washed them to hang up to dry I'm not having to always change one of the legs

I've asked and I've threatened but alas nothing changes. AIBU to ask this of a 14 yo and if not what threat should I use and carry out?

I've previously threatened to empty the contents of the kitchen bin on his bed.

As my boys were growing up I opted not to get into teenage angst situations with them.

I would ask them to do things, just basic like dishwasher, tidying their mess, bringing laundry down etc. I never went into their rooms so if they didn't bring down laundry it didn't get done. A few incidents of not having clean uniform or pe kit soon concentrated their minds.

With everything else if they didn't do it I did it myself without comment. Then the next time they asked me for something, a lift, dinner, money etc I would simply, and calmly, say no sorry and completely ignore any fallout.

Worked a treat and they quickly learned help gains help.