I own a landscaping company and tell all my residential customers that I’d rather not take their money year after year for an unnecessary service. The truth is(at least here in Utah) you just need to turn off the stop and waste valve and the system should drain automatically. I warranty all of our installs for a year to make sure everyone goes through a winter and doesn’t have any problems in the spring. If there is an issue, and something happens to freeze and break, we repair it, and install an additional drain right at the spot of the break to ensure that it won’t happen again.
I’d rather you pay me for a single repair than to continue to pay me every year for something you really don’t need. Then maybe you’ll call me when you have any other landscaping needs. Just my way of seeing it.