Apologies if the answer to this is obvious to veterans.. as a rookie I'm not seeing it.. Suppose you sell an European OTM put on an index. Then sh*t hits the fan and 3 days before expiration the market is way down and your put is ITM. You buy back the puts at a loss but offset the loss by selling the next month's puts at the same strike price. In other words, you get a credit. Repeat every month until the puts are no longer ITM. I'm obviously missing something .. otherwise it would be possible to never get a month with a debit.