Then you have slow* computers, or an inbox of 50GB+ of emails over the last decade. I've got about 20k (maybe around 15GB) email after archiving a bunch of data to a .PST, and it's much snapper.

I have to hang onto my old emails, but I'll archive to a local file since I don't need them all the time. I do it by every year, it's very helpful, makes Outlook Classic very fast again. The nice thing is the archives go into the Documents which is then backed up through OneDrive.