My A/C unit is fairly new but there are signs the condenser unit fan is starting to go. Since it is still under warranty for parts (not labor) I thought I would be able to just get a replacement fan and install it myself. But no, the manufacturer will only deal with a "certified technician," who of course charges an outrageous amount of money (many hundreds of dollars) to replace the fan. When I asked the technician why the labor cost so much, they gave me some song and dance about how the prices were set by their central office (true) and that the cost also included filing the paperwork to make a warranty claim (seriously?).
At the end of the day, I could probably buy an aftermarket fan off the Internet and install it myself, spending far less than the certified technician would charge to install the "free" OEM replacement part.
Just as a data point for those in Canada (maybe US, but I'm not sure if it's the same company), I have a Senville unit, bought from their website, and they sent a replacement plastic (yes, it's a plastic bead in a piece of rubber) bearing for the indoor fan for free with shipping free too a few years ago, after providing the unit's serial number and the original name on the receipt. The unit was in-warranty. They claim that you have to have the unit professionally installed to get the warranty, but nobody asked for this at any point (could have been due to triviality of the part). Either way I was pleasantly surprised by the willingness to provide parts, even though the documentation of part numbers and models/generations on their site isn't super clear.
It's now out of warranty, but most of these units are built by either Gree (some Trane, Tosot, Gree, some Lennox iirc) or Midea (MrCool, Eco-Air, Senville, Pioneer, Carrier), so searching for the "canonical name" of your system can be helpful in finding parts. (usually, its of a pattern like "M5OG-48HFN1-M", can be found with meticulous googling for catalogs). There is a lot of parts commonality between units. You have to be creative with finding parts on AliExpress as they go by any number of names that you wouldn't expect, and a lot of this stuff is bought by eye (or random dimensions, of which there are some canonical ones for each part) and not by part number unfortunately.
This reads similarly to how with certain medical insurance you only pay a flat $5 (instead of the full price of $25+) for common meds that you can get for $1.50 outside of insurance...
At the end of the day, I could probably buy an aftermarket fan off the Internet and install it myself, spending far less than the certified technician would charge to install the "free" OEM replacement part.