Yup, it's worthwhile to check the balance of every new prop. If nothing more, you catch the few that actually are out of balance.

Most of the reinforced synthetics nowadays are going to be very good. You may never find one that is bad. But I have. So I check 'em all.

And all the wooden ones should be checked. More of them need balancing. And some, I simply take back to the LHS. They don't mind, 'cause they say you don't need to balance props nowadays.