I Instruct now but I found differentials to be the best...such as providing a complete pressure wash before the first open house.  Tell 5 to the left 5 to the right and 10 across the street.. discounted PW this week.  I place a supreme level Warranty at my expense.  Peace of mind and the Buyer usage sends me a notice...converts Buyers to referrals It is a more valuable gift write off and word of mouth cant be beat..total investment $550 warranty and $175 PW  beat mailings at #600+ to the trash in 11 seconds.  Another permanent gift Cutlery with logo and name and number engraved.  stays in the kitchen!