You can negotiate for the option payments to count toward the purchase price, or have some portion count toward the purchase price. Having less than 100% go toward the purchase is an incentive for the buyer to exercise the option sooner. In my case, with a relatively short option period expiring before the end of the calendar year, the option payments counted toward the purchase price. Had it been a longer option period, or if the buyer had asked for an extension, I would have negotiated for only a portion of the payments to go toward the purchase...