When to ask best man/groomsmen?

I've asked my bridesmaids already, but my H2B hasn't even decided on who he wants yet. I know it's 10 months away, but I thought it was one of the first things to be done. When did your H2Bs ask theirs?

H2b asked his over the phone when we were registering the marraige! We needed his dob for the forms! We registered in December and got married in July so with about 7 months to go!