i think going solo is the way to go. Since theres no way to know what you may run into, we schedule based on enough time to turn on water, test the RP, and do a walk thru, plus drivetime; 8-10 per day is probably a good average. I will replace broken heads, fix cut funny pipe, anything i can fix quickly right then and there. We go to quarter hour billing after 30 min on site. I dont like to spend much over 30 minutes while im doing a start-up because it puts me behind and starts becoming a costly surprise for the homeowner. I schedule a few extra when they are close together or zero lots and systems that take over an hour to startup go straight to the standard hourly service charge.
Anything I need help to fix, im going to reschedule for a later date. So i may fill a day with a couple repairs mixed with some start-ups of larger systems, and pull a guy off the install crew. Or i may only do 6 start-ups and schedule 2 hours to make a repair by myself. I also keep a list of systems that i can go to at anytime; to finish out an early day, or pick up one that I missed the day before.
it works well and keeps everything moving, I do the best i can to get the system operational or diagnos the problem in the alloted time. but it keeps from constantly shifting the schedule around, and allows me to stay sane when half of jim bobs system doesnt work and ive still got 5 more systems to turn on and its 2 o'clock in the afternoon.