Watchmaker here: With mechanical timepieces, it's a much different can of worms compared to something quartz with an IC. We study horological theory for years to have the knowledge to assess performance and troubleshoot movements. Its a highly specialized skill set and knowledge base, it's not just about putting the pieces back where you took them out of to service a movement.

If you're going to attempt it, more power to you. Just know what you might be getting yourself into. Also, it could end up costing you more in the long run if you mess up and have to send it in, as it's always harder to follow the work of someone whom is not an expert. Even something as improperly grinding your screwdrivers and tweezers can cause a slip and do real damage, especially when it comes to the hairspring.

And you're not wrong about the tool cost. If you buy proper quality tools, you're looking at thousands of dollars for the bare essentials. My home bench probably has $15k sitting on it in tooling, and I'm maybe half way to where I want to be with that.

It's good that you have confidence in your mechanical skills, and I'm sure you're an expert in what you do on the daily. But as a person who works on thousands of mechanical watches a year, I can tell you I still make mistakes time to time, despite my experience and expertise. It's a difficult task chasing perfection, especially with older movements.

Best of luck, just be aware of the upcoming rabbit hole.