Thats been my point all along for HVAC systems... A good tech can
diagnose
the system, show you what the problem(s) is/are, correct those problems
with
parts from his well stocked service truck, and warranty those repairs
.....
usually for 1 year.

You are fortunate that you can do the work for yourself, and don't have to
rely on locating a good tech. As we have discussed before, the waters are
treacherous!

The waters are even more treacherous when looking for a tech to hire and
train for an employee.