fert and squirt would be nice to do only, but I find in my area I need mowing to keep things going.
I did some math the other day on a few accounts. I estimated that for a $60 app customer who I treat 6 times(6x$30 profit), aerate($100 profit), and seed($30 profit) that I made 160 profit(I was just figuring in my head and not exactly sure). That same customer is a $35 mow. Now if I figure $5 profit per mow(which might be low) x 35 visits I make $175 profit.
For the year my bottom line profit is better on mowing, but then you need to figure in 35 mowing visits vs 8-10 app visits.
It's all about learning and customer satisfaction. You will find that residential customers are very loyal. I'm hoping my app side takes off since there are few app companies here.