It takes a while, but it shouldn't take THAT long. I'd say, after an hour of the spinning beach ball of death, I'd do a hard restart (or cut the power) and try restarting. If still no luck, it might be time to visit the Apple Store....🙁
Sorry, that sucks.
Disclaimer: Hard restarts and cutting power are done at your own risk! I'm sure others will tell you to absolutely never do this, but it has worked for me in the past.