How far ahead should you buy your fh wedding band?

My engagement ring and band were part of a set, so a little more than a year and a half. We're still waiting on FH's band since he's so indecisive. BUT we do still have more than a year to go

We bought ours super early, I convinced him to try some rings on and he found one he loved and I found the wedding band I loved (which were both on sale) so we bought them right there.

Mine bought his about a year in advance but he was being extra lol

I wouldn't say you need to until 406 months before