Maybe this isn't quite a Mustachian problem, but
I recently got a Sallie Mae Mastercard (great card by the way, 5% back on first $250/250/750 of groceries/gas/bookstores every month, Amazon is a bookstore, don't need Sallie Mae loans to apply - can get statement credits for rewards). I want to change the statement cycle so it ends just a bit before the end of the month. But they won't let me specify the statement cycle! They only let me specify the payment due date.
I don't care about the due date! I want to consolidate all my statements to the end of the month, when I balance out YNAB and whatnot, and then pay them off immediately.
And yea yea, I know, the payment date is three days before the end of the next cycle. A minor annoyance, I know.