I think I wash my hair with any product once or twice a year, and only if I’ve had something in it (lice warning at kids school, sprayed with mud from a hike or similar) and then literally use a drop of shampoo. The less I wash it the better it looks.

Hair products are a lie. Water and a scrub is way better.

My hair is short. No idea if the same applies to long hair. I suspect it does.

you joke but that's basically true, at least for some people.

I stopped using shampoo outside of special occasions and after like a month of my scalp vomiting grease it realized i wasn't constantly removing it and calmed down. Now my hair just constantly looks like i shampooed it a day ago, and it takes only the tiniest amount of shampoo to be effective.

I recommend just trying ramping down your shampoo usage gradually to nothing, and waiting as long as you can tolerate to see if your scalp stops overcompensating, and then only using as much shampoo as is actually needed for you to be satisfied.

Not only is it way nicer, it's gonna save you a bunch of money too.

You'd be better off without the shampoo, provided you use the right kind of conditioner (without silicone, waxes, etc). Look into co-washing and the Curly Girl method. Ignore the "girl" part, hair is hair. For several years, my hair has felt so much better and doesn't look flat.