We're not talking rocket surgery here. Familiarize yourself with the components (you can pick up free literature at Home Depot), carefully observe how your system is installed, discuss with the installers what they are doing, and why (most of them love to talk), and you can easily maintain your system yourself.

Awesome. Thanks for that!

Sousvide, yearly maintenance pretty well includes winterization. Even in the lower mainland (I'm up in interior BC) I would still reccomend having your system blown out in fall. Either you can rent a compressor and do it yourself (being careful to keep the pressure appropriate, its a blow out, not blow up!) Perhaps split the cost with some neighbors, or hire a landscaping company to do it for you. Depending on the size of your system and time required, this should cost between $40 and $90. Of course, you could also pay to have your system start up (and potential repairs) done in the spring, and pay for a tech to come make your seasonal adjustments for you too, but I would side with whitecap on that one, learn your system, they are fairly easy to maintain on your own.

The main cost of a system is the labor to get the pipes in the ground and the sprinkler heads on them. And a good designer so you get good coverage.

If the system is installed with a "drain-down" sump you can avoid the "blow out". That may or may not work for you and your climate. But protect the pipes.

The parts are not expensive, it's the labor that makes repairs expensive. And they tend to last a long time unless they freeze.

New valve: $20 (failed in a 1990s system - leaked)
Plumber to put new valve in: 90-150
Time to do it myself: About an hour

Vacuum Breaker: $105 (it FROZE in Phoenix! It's now insulated)
Replaced it myself.

The risers and heads are not expensive - if you chew one up with the lawn mower, it's easy to replace. Keep a couple of spares

Controllers tend to last a long time if they are installed inside or at least in a sheltered location. If you have to change out a controller, the valves are standard. It's really plug-and-play.

Since I'm in Central Texas, I don't have to worry about "winterization." I have drain plugs at all the low points. But I'm wondering about this pressurization business. Where and how does one inject the air? Can this be done with an inexpensive air compressor, of the type that one might keep at hand for the occasional flat tire?

Replacing valves can be tricky, but you can get the advice you need here, when the occasion demands. They should last 7 or 8 years, anyway.

Whitecap, we build our systems up here with a blow out port. Usually its a hose bib or 3/4" thread T with plug or cap, typically the first thing on the pipe ouside, often before it hits the dirt. We use the trailer sized compressors in the fall. Shut off the water from the inside, bleed/ drain the pipe, hookup the compressor, and force air through the zones until the water has all been blown out. For a residential system I run at around 40- 80psi depeding on the system build size and age. I've seen homeowners diy it though and shoot ther spray nozzles right off the bodies at 100+psi.

Learn something every day.