Since everyone’s hair and scalp are different, it’s hard to predict what will work best for you. I would suggest that you make a gradual transition to going shampoo free!
I would suggest you start with less frequent shampoos. Starting with every other day, to every third day and so on. Make these changes slowly, maybe three weeks for each stage.
Next, try replacing every other shampoo with a combination of Apple Cider Vinegar (ACV) and baking soda; use some baking soda, mixed with enough water to make a paste, and scrub your scalp with it. Since it’s the scalp that produces oil, focus your efforts there. Rinse your hair with a combination of ACV and water; splash some on your head, scrub a bit, splash more and scrub. If you can’t rinse all the baking soda away, or just want your head free of both, feel free to rinse with water. The ACV neutralizes the baking soda, and cleans your scalp.
This all may not work for you, depending on your age and your scalp’s production of oils. I think that younger people, who exercize a lot, tend to have oilier scalps. Plus the humidity and the sweat you produce might be too much to allow for a no shampoo regimen. But I think you’ll be able to at least reduce your use of shampoo if you transition gradually, from shampooing less often, to replacing shampoo with ACV and baking soda.
That’s how I started, and I like my hair a lot better now. I’ve even gotten compliments! I have less frizz, almost none, and my scalp doesn’t smell, even after a month without even rinsing! But I’m white, and I know people with natural hair (black) have hair problems that I have no clue about. Also, I live in the NE US, and humidity is not a problem most of the year.
Sorry for the long post. I tend to write too much. Good luck!