Hi Ranchulover, and welcome to our board, first of all! Wwe seem to be fond of the same kind of goldfish here...
I have had goldies for over 5 years now, and hardly ever have the airpumps off. They run constantly day and night. There are brands out there which are a bit more noisy, and then some, like the Rena brand, that you dont hear at all, for many years to come. Its a thing of personal preference, I guess. If you would have your tank in the bedroom and a rather noisy pump, you might wonna turn it off at night to get some decent sleep. Otherwise, they are running all the time...