Now I am in no way a hair expert but I have managed to go from having to wash my hair every 1-2 days to often being able to go 3-4, which for me is a massive help as I find it such a chore washing/drying hair. I have super oily hair and it would often go greasy practically the day after washing so I would spritz it with dry shampoo constantly and hope for the best. That is until I learnt that you can actually train your hair into going longer between washes and these are some of the things I found helped with that.
Start off slowly. There is very little point going from washing your hair every day/other day to washing it ever forth day as all you'll be left with is a greasy mess that no amount of dry shampoo could save. You have to start off with a small change and gradually build up to the desire time. So begin with skipping one day and then once your hair seems okay with that, move on to another until you find that your hair has completely adapted to your new schedule.
Find a shampoo for your hair. Despite the many beauty blogs recommending various different shampoo/conditioner combos to try, these might not necessarily be the right ones for you and your hair. If you have oily hair already, don't use a shampoo infused with extra 'shine' oils as this will just add to your already oily scalp. If you have dry hair though, the need to over compensate with super nourishing shampoos may actually be the reason you are having to wash your hair more often. I personally have oily hair so I find using the Bumble and Bumble Sunday Shampoo once a week works well to deep clean my hair and then my ordinary silver shampoo to keep my colour - neither of which contain extra oils.
Don't use too many oily products. This may seem like an obvious one but you'd be surprised how tempting it is to just run some Moroccan oil through the ends of your hair or use a conditioner mask, when in reality, your hair may not actually need this extra moisture. If you're hair isn't in really bad condition, you most probably don't need all these extra products loading up your hair so try to use just one (or none) and this will help keep the grease away longer.
Only use dry shampoo when you really need it. There's always the temptation to blast your hair with your favourite scented Batiste dry shampoo the second it starts to go flat but don't. Although dry shampoo is great for adding that extra grit and volume to your hair, it's actually counter-productive if you're trying to go longer between washes and it often leaves my hair feeling worse, sooner.
Don't touch your hair. Touching your hair frequently actually makes it go greasier, quicker. This is definitely one I still struggle with as I'm constantly twirling my hair between my fingers but if you touch your hair less, you'll find it helps with not having to wash it as often. A tip I find works is to tie your hair up whenever you can while you're not doing anything to a. keep it away from your face (better for your skin) and b. to stop the dirt from your hands spreading to it.
Do you have any tips to go longer between washes?
