Ask HN: Do you really issue 10M shares at incorporation?

Hey there - I'm doing some research on how many shares you should "create" at incorporation to issue to your cofounders. I've talked to a few people who say the number is arbitrary and that you can increase the number of shares issued with a board resolution before a priced round; I've also read that it's common to issue 10,000,000 shares initially (still before a priced round).

Are there any ramifications for not issuing enough shares and needing to add more, and, vice versa - issuing too many?

Thanks!