I do the same as cmor - mag float daily, scraper weekly.
One thing though... if you keep your mag float attached to the glass and in the tank, it will end up growing algae on itself and as someone already noted, become more of an "algae smearing pad" versus an algae cleaning pad. Yeah... it's convenient, but ends up reducing its effectiveness.
I take my magnet cleaner out of the tank after each cleaning and dry it off. It's still almost as clean as the day I got it.