Something that made hygiene-related things easier to do was to say “fuck it” to the concept of doing the thing at the Right time. My teeth do not understand that it is currently 02:00 or 15:00 and they’re getting brushed. The skin on my face doesn’t hold up a timepiece and say, “why haven’t you washed me, twelve hours have elapsed and you haven’t bothered to wash me!”.
As someone who has had very intense experiences with my ability to do things at the Right time, throwing out those rules has been a game-changer. I used to shame myself because I didn’t do something at the Right Time, so I just didn’t do it, which would make me feel even worse. That’s not a healthy way to go about anything. Accommodate for yourself. Throw out those rules.