Actually I am not that well versed as a mechanic. But these days I know that I can find the best price on auto parts online and then, with some help from a decent YT vid.. I can do it myself. When the company I worked for went out of business 3 years ago.. I found myself almost immediately needing a brake job on my 06' Dodge Ram. Disc brakes. The last time I did brakes it was drums, I had never done discs. I found sporty slotted and drilled discs and high end ceramic pads on Ebay and had them shipped from Cali to Ft. Lauderdale for $240. Great price! With $25.00 in brake cleaner and caliper paint I fixed them myself. I decided while I was in there I was going to paint the calipers fire red like you see on sportier cars these days. Still looking nice and red. I will say that I ignore puddles, being in a truck with large tires... and I think I had warped one of the discs... I got a wobble braking at high speeds. I don't believe in turning discs at the garage... so I just redid them all 2 months ago. They probably would last some peeps longer... but the truck is heavy and I do a ton of stop n go here in the Miami area. (see what I just did with the "heavy" and "ton")?? I recently cleaned several sensors on the truck with some cleaner from the auto store... via a video ala YT.
I've replaced everything on cars from headlights to engines and transmissions, but one thing I will not do ever again is AC. It's too tricky.
The slightest bit of dirt in the system and the expansion valves malfunction. If the system is partially discharged I'd recharge the freon or puron, but once they are totally drained and have holes they get moisture and dirt in the system and pretty much need to be rebuilt. IMO when that happens spend the little bit extra I've found and take it to someone that specializes in it, or someone you are confident can rebuild a clean system.