Other than the fact that Leslies wants to sell me unnecessary chemicals, why shouldn't I use their free service? OK, I am not going there every day, but if I go there once or twice a week I save 20% or more on the cost of doing it myself. They sell, and seem to use Taylor test products just like TFT100. Is it just because of consistency, using the same test kit every day? Newb trying to figure it all out