Most of us try and keep our machines cleaned periodically from dust and all that. I just retired last year as a heavy machinist where a lot of the work is cast iron. They used a lot of low end Windows NT and 95 desktops and some lasted for 10-15 years with no maintenance. They were always on and the main reason they replaced them was because they wouldn't work with new software or were ungodly slow. It kind of boggles the mind how they lasted that long in that filthy environment. The were still using a few Windows 2000 boxes when I retired. They replcaced the NT unit that my CNC machine was connected to with XP in 2007. They got their money's worth out of them out in the shops.
Joe
Joe