I have 2 DDs, 5 and 3. The 3 year old has always flatly refused to do any tidying up, putting books back on shelves, putting particular named pile of things into named particular box. When they have jointly made a mess with jointly owned toys, and it's time to sort them out, or the toy room gets knee deep and a friend is coming to play tomorrow (that's today's case), it ends up with DD putting away, reluctantly, with a lot of guidance and breaking up the task into small bits, and DD2 just fannying about and blankly refusing to put thing A in the green box.
I and DD1 both think she is perfectly capable but is enjoying getting away with it. I can't put half of the jointly owned toys, and that is most of them, in time out, and she doesn't care about being in time out and just winds DD2 up about not helping.
How do you sort out problems like this??