I stopped washing my hair every second day years ago and it made a BIG difference to my hair health. I now wash roughly every 5 days but can stretch it out to 7, maybe even 8, with a bit of dry shampoo. Certainly easier to get away with this in winter and when I’m not doing super sweaty workouts!
My hair seems a lot healthier the less I wash it which seems counterintitiive but I guess makes sense when you think about how your hair oils are produced!
I think I could push it to 10+ days but psychologically I don’t think I could do it!