Seriously
Many other carriers have options if payment is greater than $100 your balance does not expire.
Public even used to list 180 day plans in the past (no idea why they were ditched)
Bring in a 365 day plan. Just pay it and forget it.
Even from a support viewpoint, if payment is made once far less Mod interaction is required (even if repeating billing error, 1 fix vs 4+ fixes a year seems a no brainer)
From a revenue standpoint it is a winner since you are deferring when rewards are acumulated to end of year (interest free loan) as well as guaranteed revenue (since no worry client could cancel)
From an infrastructure point of view less system wear and tear since clients can not be switching plans every couple months or jumping on every promo flash sale you introduce
The only negative is forums might quiet down if people check online less often (but really do we want nervous people who need to check their accounts every month to see if something worked or not?)