Honestly, it depends on what stage I'm in.
On my lower, lower stages... I admit, I can go days without a shower or a teeth brushing. I just start to neglect myself. I'll reach a point where I'll tell myself "Eh, I'll do it tomorrow," tomorrow comes and I tell myself "I'll do it tomorrow," again. I don't want to neglect myself and do realize personal hygiene is important - but when I'm in those moods, I feel like it doesn't matter, anyway.
Then, when I'm in my better moods or whatever you'd call them (idk, heck, I haven't seen a doc in a while, all I know is what I was diagnosed with a while ago), I get to a point where I become obsessive about it. I'll feel completely and utterly disgusted if I don't shower and will shower obsessively for several days and my teeth will start bothering me even if I've already brushed them twice in that day and I'll have to brush them again.
Really, my personal hygiene habits fluctuate.
ETA: Also, I can't remember who made the comment about the car wash... but it made me laugh so hard that my dog looked at me as if I'd lost my mind.