My main machine is actually a x200s. It's a perfectly fine machine for my daily needs, free software development, browsing the web, etc. If it is a machine li

My main machine is actually a x200s. It's a perfectly fine machine for my daily needs, free software development, browsing the web, etc. If it is a machine like that I'd suggest to keep using it and treating it just like any other machine. You could even get rid of the hardware backdoor (ME+AMT) by replacing the BIOS with libreboot and use it as a slightly more secure machine for crypto. If it's considerably older than that it might still be sufficient for software development, so you could either sell it, or have a refurbisher sell it, or donate it to projects like a local CoderDojo group.