I use it 3-4 times a week and I don't get dry scalp. I love how my scalp feels. I wish I could use nizoral on my oily face, but I don't want a hairy face. The growth stimulant in nizoral is pretty strong.
I'm thinking of using nizoral every other day, and then having my experimental shampoo every other day rotated with it, and not buying any more piroctone olamine. My experimental shampoo is cheaper, and I think it will be stronger too. The piroctone olamine shampoo is probably very stable, so I can just use it up slowly on the few days that I shampoo twice in a day, or use it once a week.
For $1.12 at walmart, I get the lavendar/chamomile baby shampoo, equate brand. I add a tiny bit of arginine and alpha lipoic acid, 1% spironolactone, 1% licorice extract, 1/2 mL of lavendar essential oil, 1/2 mL of peppermint essential oil, 0.5% white curcumin, a little bit of apple poly and EGCG. I add some polysorbate 80, PG, and aloe vera to help mix it and increase absorption. It all dissolves in less than 1 minute. These ingredients are cheap and will last years, except for the spironolactone, which costs $7. I only use the spironolactone version on my head, and a non-spironolactone version on my body.