Your supposed to change them? 😂😂😂
But, yeah like others said, it depends on what I'm doing and how soiled they get. I have a pair I wear only when I'm painting (for obvious reasons) I have a pair I wear when crawling under a house (hope to cut that out) I have a pair for when I perform maintenance on the tractors or backhoe. And then there is the ones I wear for general carpentry.
Can be from a day to a couple weeks depending on how soiled they get.
I have some "oil changing" pants that look rough - They'll be cleaned but are still stained and ripped. I'll be wearing them around the house to do work and wife will want to run an errand somewhere. I never change. I just wear them wherever we go.
To her credit, she's never said boo about it to me.