I 'revived' an old computer. I added 4gb ram, to go from 4 to 8. I added a small, 120gb SSD, to function as main OS and programs drive with a mechanical hard driver for everything else. It made a huge difference. Now the computer boots up to desktop very fast. Programs start very fast. In my web browser I used to have to close tabs at a certain point if I wanted to open new ones because the computer would get sluggish. Now I can have a totally ridiculous number of tabs open in multiple browsers(Opera, Firefox, Vivaldi) and the computer stays responsive at all times.
So I think you're going to be happy with all this once you're done.