You really don't even need to do blowouts in Colorado (even though I used to do blowouts as a side gig years ago). It doesn't freeze deep enough to burst lines (if they're buried deep enough which isn't all that deep in Colorado) and only occasionally will you have to replace a cracked head and that's like a $5 fix & a 2min process in most instances. I keep an eye on the upcoming weather and if it's going to get below freezing I turn off the sprinkler supply valve in the basement, open up the little drain valve and then open the check balls on the backflow siphon and let the water drain from it. Worse case scenario you break a vaccum breaker and the parts are about $30 at Home Depot w/o any coupons and you can change them out in about 5min time. Other than that, I don't do blowouts or turn ons because mine are basically on year round. It gets VERY dry in Colorado in the winter and it's wise to give your yard a good drink a few times in the winter too when we get those long periods of dry, windy weather to keep things happy.