Hard drive? optical drive? keyboard? mouse? WIFi, Bluetooth, Software suite? Cables? Warranty? Tech support?
I think you omitted a few things. Your time? Or do you work for free?
Hard drive and dvd burner has been covered. I have dozens of keyboards and mice because you can pick them up dirt cheap for pc’s. Same with wifi, bluetooth, cables, etc.
Warranty? For what? Each part has a manufacturer’s warranty.
Tech support? Why would I pay someone for something I can do myself?
My time? Yes, it’s free, it’s minimal, and I enjoy doing it.
As has been mentioned numerous times, it’s not for everyone.
Not comfortable doing it? Don’t.