“What I'm trying to come up with for the Lincoln dealer is for ($$$.$$) price per new car you sell I will offer them unlimited washes for that vehicle for the life they own it.”
Ok, math problem.
40 customers a year, Edmunds pegs Lincoln trade-in at 7-years and assume unlimited wash 4 to 5 times per month and unit variable cost is $1.75.
One customer cost = 7-yrs X 4.5 washes per month X 12 months X $1.75 = $661.50 or 378 washes per customer
Add on $132.30 or 20 percent profit margin and cost becomes $793.80
40 customers = one-time profit of $5,292 and 15,120 potential washes annually for 7-years or 105,840 washes if everyone comes to the party
Year 2 generates another 40 customers, another one-time profit of $5,292 as well as another 15,120 potential washes annually for 7-years or another 105,840 washes
Year 3 and so forth until program is terminated.
So, in year three of program, there would be the possibility of 120 people showing up to wash on the same busy Saturday. None of these people has incentive to give you any more money for as long as they own and choose to wash.
Conversely, express sells unlimited for $19.95 X 12 months is $239.40 per year.
Lincoln program is priced at only $113.40 per year contractually committed for say 7-years.
$793 seems like a lot to add on to car price considering add-ons like paint sealant and fabric protection is $500 or so.
Also seems like a lot of potential wear and tear on equipment if redemption rate is high.