I used to buy the cheap power tools at my local department store. They are just made for occasional home use not daily use on the job. However, I have been impressed with a few brands. I still have one drill that I bought back when I was about 18. I’m in my 50s, and that old drill with the power cord still works. I am not sure you can get that longevity out of even the pro battery-powered drills. You definitely won’t get 30 years of use out of the batteries. I shop for power tool parts in Canada, and I get batteries and other replacement parts for the tools I own. I have never had to replace anything on that corded drill. Granted, I do not use it every day like some other tools, but it sure has taken a beating and still works.
I shop for power tool parts in Canada online at a website that lets me save on shipping to my Canadian address, and I can pay in Canadian money. I used to buy a lot of parts from companies in the United States. I would pay extra for shipping and had to pay in American Dollars. This is easier for me. Things I usually need are replacement batteries or brushes for some motors. I have replaced a cracked housing or two as well. It is not difficult to do that. Most of the power tools easily come apart by taking out a few screws.
I burned out a chuck on a drill once. It turned out to be cheaper to fix it than replace it. When you have to use your tools for a living, you want to save money keeping them working. Still, I would say that the biggest thing I come up against is replacing batteries. They only last so long before you really need to get new ones to have full power and a long lasting charge.