Instead of saying "I don't have time" try saying "it's not a priority" and see how that feels. Often that's a perfectly adequate explanation. I have time to iron my sheets, I just don't want to. But other things are harder. Try it:

"I'm not going to edit your resume, sweetie, because it's not a priority."

"I don't go to the doctor because my health is not a priority."

If these phrases don't sit well, that's the point. Changing our language reminds us that time is a choice. If we don't like how we're spending an hour, we can choose differently.