First off, let me introduce myself. I work for a small company in a rural area of Washington with many retiree's that have lots of money and nothing to do with it Therefore, the landscaping and irrigation business is booming. Our company is the only company in the area that just does strictly irrigation. We've been around 18 years and have a very well established client list. Around here, it seems like all the landscapers do a rather shoddy job, from using thin pipe (a bad idea in our horribly rocky soil) to cheap heads and slip valves. Some of the things I prefer to do/use: Use a vibratory plow as much as possible to reduce damage. Use only Sch 40 pipe, only as small a 3/4" for a water line, proper calculation of zone sizes lets us usually run 1" or 1 1/4" mains. Use Rainbird DVF threaded valves... I hate slip valves, and cannot fathom why anyone would use them. Use funny pipe swing joints on all heads. Use only Hunter PGP's for rotors and Rainbird 1800's for Sprays, occasionally use a Toro Streamrotor for landscapes on customers request. Prefer to have valve manifolds with only 2-3 valve boxes per job, instead of many single valve round boxs. Use multiconductor Direct Burialcolor coded irrigation wire, instead of single conductor wire. Occasionally we will pull in 1/2" conduit for it. Anyone else care to list some of their preferences?