I've never heard of an insurance month either. Diamond members accrue five days per month, so if you go into vacation mode, as your three months run out you'll accrue another 15 days, plus another 2.5 days if the extra 15 days runs over the 1st or 15th of the month (it usually will), or 5 days if it runs over both the 1st and 15th of the month (it rarely will).
So extra vacation time accruing during vacation time could add up to another 20 days.
Add in 10 or 14 days for a slow time control and a titled player could have an unfinished game hanging around for up to four months.
Does it work that way?
I thing we don't accrue more days while we are on vacation. It's a kind of contradiction. The maximum wouldn't be 30 or 60 or 90 in that way, for example for a basic member would be 30 + 2 (a basic member get 1 day every 15, right?)
Can you still accrue a maximum of 90 days vacation?
What's the logic for such an absurdly high number?