I've used two scanners.
My Epson 2400 has provisions for scanning slides and the reults are not horrible.
I have borrowed old Olympus ES-10 film / slide scanner. Its results are pretty good but I keep wanting to refocus.
Both are enough of a pain to use that most of my slides remain unscanned.
My view is that your time would have to be worth relatively little to consider scanning a lot slides yourself. For a small number of slides, the cost of the scanner amortized over the few scans would make it uneconomical to do the scanning yourself.
To be honest, I haven't enquired about the price of commercial scanning services. Sticker shock might change the view I expressed above.
seacue