One of our competitors in our area is fert/squirt only. He uses a program which uses something like google maps and he gets 250 lawns a day measured, then does mass mailings to those with a price based on sq. ft. It costs him a ton i'm sure. He claims his response rate is 1/3 of 1%. In layman's terms he lands one of 300 proposals. he mails out about 50,000 of these. Round up to 60,000 that would mean he gets 200 accounts from 180,000 mailings as he mails out 3X's to the same people at 3 week intervals. He claims to start turning a profit after mid-summer. I say b.s. that there is too much outlay in printing, mailing, and time spent on the calculations. If they stick with him long term, maybe.
If you fail to plan ..... you plan to fail.