How do you manage self-care and personal hygiene?

I'm embarassed to admit that I rarely manage to shower twice a week - usually it's once, on the weekends - and that I brush my teeth at most three times a week if I'm having a really good week (some weeks, I don't do it at all). I also forget to change clothes. I usually change into another shirt every two days, but sometimes I'm walking around in the same trousers or socks for (over) a week.

How do you do this?