Last year I knew all the answers. HOWEVER...this year they changed the questions.
Nothing stays the same. New diseases. New grass types. New equipment. New fertilizers. New herbicides, (which cost more). New weeds. New regulations. New business practices. Cost increases. Strange weather. New competition. Information technology.
If you keep doing it the way you did 5 years ago, competitive pressures will really start to squeeze you. Myself (as I am retired) I don't get calls from the chemical salesmen anymore. I don't go to association meetings anymore. I have to read a lot of online information trying to keep up. Lots of information right on this site.
A few years ago my wife bought me this gadget--I didn't think I needed it. It was a cell phone.
Competition never lets up...customer satisfaction pays your bills.