I have my guys write our in time and the out time for work performed with the exception of mowing. I also use RealTrack GPS on my maintenance truck. I can back up my billable info with GPS reports. RealTrack is only $18 a month. If you run even just one crew like myself you crazy not to be paying only 59 cents a day for GPS. I had one a-hole client try to tell me we had not mowed his lawn last year. I mentioned GPS and he had the balls to suggest my guys were just sitting in front of his house. I just happened to talk to a customer across the street that week and she told me as we talked that she could see my guys mowing the client in questions yard. When I emailed the customer that his neighbor saw us mowing his yard and that she could confirm the mowing was performed his reply was that he thought my feedback was bizarre. The only thing bizarre was I was able to counter everything the guy said and I took the wind out of the SOB's sails in a big way. A month later he was no longer a customer. Good riddance.