One of the tenants over at my parents' rental property called me at 6:30 this morning to tell me that his furnace wasn't working. So I get up and get dressed and head over. I get the furnace apart, and I can see that there is a capacitor that is all burnt looking. Its a Trane furnace, and Trane supply is closed on Saturday, so I call a buddy of mine who does HVAC and knows some people at Trane. Fortunately he had a couple capacitors on hand, so I drove over his house on the far side of town and grabbed one. I get back, swap it out which takes all of 30 seconds, and the furnace kicks on and is putting out heat. Now it's about 9:00. So I pack up my tools, get in the car and I'm about to pull out of the driveway and this tenant comes running outside in the snow still in pajamas yelling and waving his arms at me to stop. So I roll down my window and he says "Oh it's making this awful noise, its screeching and squealing." So I go back inside and yeah, it's making a noise. So I stop it and open it up, and then turn it on again, and the noise is from the blower motor. Now I'm thinking "Fuck, I'm gonna have to replace this whole fucking blower assembly." Then I remembered when I replaced the furnace in my house a couple years ago, I kept the blower assembly from it and I think they are the same furnace. So I go back to my house, dig this old blower assembly out of storage, drive back over to the rental property, get the bad blower assembly removed (it was covered in dust and shit that certainly got into the bearings and ate them up, I've never seen one that was this filthy inside), and the replacement one I have is too big. So I took the assemblies themselves apart and swapped just the motors which are the same. I swap the motors, get it back together, start it up and it's now working.
So it took up my whole morning, but no doubt if I called a furnace guy they would've been trying to sell me a new furnace.