People may think that it's only saving a few dollars, but it's more about the control you have. Doing it whenever you want, no appointments, no waiting, no hassles with the upsell. Knowing that you are getting a proper oil change. Plus it feels good to do things yourself, and it seems like a lot of fun. I think I can save $100. That is like 5 hours pay for me. So why not?
I would like to teach myself more about cars so I can do other things such as brakes, etc... But one step at a time.
Another skill that I invested in is cooking. Before I could not cook to save my life. Now I can cook anything, often better than your average restaurant. It's so fun to cook, and nice to be able to eat anything I want whenever, without going to a restataurant, waiting, overpaying, and having to tip.
The point is that I would like to acquire as many skills as I can to better myself. If I can save money on top of it, it's a bonus.