A lot of people do that.
I know I like to alternate the joico kpak line for protein and giovanni or kenra for moisture.
Its not a bad idea when you find things you really like, especially if they happen to be things that come in big containers. I actually just feel back in love with TIGI dumb blond which is a lite protein and the TIGI moisture maniac. I found two big bottle at Marshalls for 14.95 a piece.