Theoretically, you could use 1% every day.
There's a study out there somewhere that supports the 1% being about as effective as the 2% in terms of hairloss prevention measures.
I actually dropped 2% about a year ago and went w/ 1% - not everyday - but pretty regularly.
In that time, I lost a fair amt of hair. There are other variables obviously, but I'm not taking any chances.
Even though I'm doing Revita 5x weekly, I just also got a bottle of Dr. Lee's regrowth shampoo (nizoral 2% & Salysilic Acid 3%) which I'll be using on my off-revita days.
In my instance - I'm just trying to make up lost ground.