Sounds good. Do you also have the new filter ready?
As for your question, weekly partial water change of 30~50% is always recommended. Tank size does not affect the maintenance routine. http://petskeepersguide.com/aquarium-mai...intenance/
The whole point of upgrading the tank size is to have better overall water quality between water changes. If you decrease the water change frequency, then it defeats the purpose of getting a bigger fish tank.
When you move everything to the 10 gallon tank, make sure the old filter won't lose any beneficial bacteria it had already gained. The old filter is the key during this transferring, and it will at least make sure your new 10 gallon won't have any more total ammonia/nitrite than the 3 gallon. Be careful when you transfer the fish. Take your time to let the fish adopt to the new water to avoid shocking the fish.
