Is regular maintenance of HVAC worth it on a rental

[Curt Bixel]

The common thought on this seems to be that you should schedule regular maintenance on your HVAC systems in rentals.  I wonder if anyone has ever really dug into this to know.  I don't really do that and I do get calls every so often from tenants about an HVAC system that is not working.  At the same time, I save the cost of the maintenance visits and I don't have to bother scheduling them and inconveniencing the tenants until there is a real need.

I imagine that there are people out there with so many rental properties that they actually have the data on how many emergency service calls they get per year despite having regularly scheduled maintenance in place and the cost of those emergency service calls.  There are likely also people out there who have many rental properties who don't have regularly scheduled maintenance in place who also have records of expenses.

I am wondering if any of these people can share their experiences. 

I imagine there is a third group of people who have really, really, strong feelings about this issue either way, but don't really have much in the way of data or experience to back their feelings up.

I am interested in hearing from anyone, but it would be helpful if you could first share the basis for your take on this issue.