How to deal with constant wet pants

[TooTweeOrNotTooTwee]

DD is 4 and at school.

She has been potty trained for 1.5 years but has never been perfect to be honest. Poos are fine (thank goodness) and she never wets a lot. But she does tiny wees in her pants all the time, basically because she needs to go but can't be bothered / is not interested / is too busy.

How do I tackle it? We've done sticker charts although that is a while back, didn't really work at the time. Also we were rewarding wees in the potty or toilet which she had no problem doing, but by then her pants are usually already wet. I've tried making her change herself but she's just not bothered and won't change unless I do it for her.

Any ideas gratefully received...