When my three sons were aged around pre teen years they would do part of jobs I asked them to do. They are now all old enough to be grandfathers but a I, and they remember it well.
I instilled in my boys responsibility for others. I was a full time working mum and my husband was a fireman in shift duty so for all this to work we ALZl had to do jobs and be responsible because I not prepared to carry the workload as the only female with four men in the house.
So,... when I realised I was constantly picking up the remnants of half finished jobs I acted quickly and amazingly the problem was soon easilysorted out - much to my relief.
When I cooked dinner, chips and egg was a favourite then Ai would cook the chips and put a fresh egg still in its shell on the plate. If half a job was ok for them, it was for me too,
I warned them wash just the fronts of boxer shorts, give them half pocket money, drop them off half way to school, give them half drinks, half size snacks for school. I can remember offering cold hot dogs and raw onions once because a I couldn’t be bothered to finish the job......you get my drift.
My tactics did not last long, everyone learned that sloppy laziness was not tolerated and it worked. No bones broken, no angry words. As my old Irish grandmother used to say “If you treat people the way they treat you you have nothing to worry about”.