Or poverty! Don't forget poverty.

Regarding long curly hair, and according to my barber: use hair cream and shampoo twice a week. Otherwise wash/rinse your hair with water only. I've been doing this for the past year.

Yea, if you shower every day, start with 2 on 1 off then transition to every other if that goes well. My routine is less rigid in that I avoid shampoo unless I did something gross. Your natural oils help thicken up the curls, but even (especially) on the days you don’t shampoo you need to wet comb your hair in order to dristeibute the oils out from the roots to the tips.

You can switch to co-wash (only conditioner) and see if that helps. There are various levels of this, from every day to once a week. You can use just water every day or every other day if you go once a week.

You can also use heavier oils in your hair for a week or two, still shampooing every few days, and just replenishing with heavy oils after. To get through your "two weeks of oily hair".

What is happening with a constantly scrubbed scalp, is that it is always in crisis mode. It is sensing it is completely free of oil and producing large amounts of oil to compensate. This is not only too much oil, but it is quickly produced, substandard, emergency oil.

You need to convince your scalp that it is safe, and that it can go back to producing smaller amounts of higher quality oil. This also means that after you get things right, when you do wash, you put some oil back in. This will keep it from going back into crisis mode.

If you can't roll around with super oily hair for two weeks, which is understandable, you can slowly try to get your scalp into this state, using limited washing, co-washing, and oil replenishment.

I... actually didn't think about it too much when I wrote cold turkey but I imagine it involves switching to less strong products that leave some oils. If anyone has a product in mind though, maybe they can chime in.

Switch to Dr Bronners Magic soap. Doesn't' destroy all your natural oils afaik. It's been my go to shampoo for growing hair out twice.

With long hair, yes. I shave my head so I actually have to oil my scalp, 1 for that fresh looking shine, and 2 without it my skin will flake and crack and in general make me look like a resident evil zombie from behind.

As a guy with short hair, I didn't wash my hair regularly for years and it was fine, but I don't have very oily or greasy hair