It all depends on the on the staffing on the airplane that you are on plus a bunch of other variables. The same goes for pay and also depends on the individuals airline contract.

The take away would be that if you commute, your opportunities are much more limited for extra pay.

Another positive of living in base is whn you are senior enough you can bid reserve and be "call last" and not have to fly if you'd rather spend a few summer months with the kids, remodel a kitchen, etc.