I was advised to continue changing mine weekly, if only to clean the gravel. What I did, when I had my 10g, was I kept my 1g bowl and used it as a sort of measuring cup for each water change. 1g changed out once per week, 10%. It worked great.
Well it really depends on how cycled your tank is. . . . if you're in the beginning stages monitor it (test) and I would change weekly - but once it's cycled you could do it at least once every 2 weeks. . .