Technology develops so rapidly that a top of the line machine designed just a few years ago may not serve your purposes today. From smaller hard drives with more storage space to virtual desktops, the world of computers is constantly changing, but that doesn't mean that you need to ditch or scrap your old computer. Instead, you can simply repurpose it.
Command Central in Functional Areas
Maybe you are one of those people who constantly hears “Can you look up ...,” or you yourself have a room where you constantly need to research things. Why not dedicate an older computer for those purposes? Put one in the garage or barn to make it easy to look up and order parts or services. Switch your VGA for a touchscreen to quickly scroll through recipes in the kitchen without worrying about the keyboard.
Storage Central
Turn your old PC into a fileserver where you and your family can store files that you commonly use, like family photos, the budget, and sensitive information that you may not want to keep in the cloud. Connect it straight to the router so that your entire network has easy access to the files, and you don't have to invest in any extra storage space.
If all else fails, you might make it a computer that the younger children can use. You may even equip it with a hosted virtual desktop so the younger generation doesn't feel like they have something less than you use on your own computer.