If you are a typical C|net user, you probably have at least one computer, a couple of mobile devices, and a smart TV or streaming device ... minimum. All of this is on a home network with some, but not all devices, wirelessly connected.
With every new or replacement device, plan for the future. Go one step higher in computer power and RAM than you think you need, because you will need it sooner than you realize; and go two or more steps up in storage, because drives fill up fast. Use Ethernet where possible to take some of the strain off your overworked Wi-Fi, and because Ethernet is usually faster anyway. Buy (or make your own) Cat6 Ethernet cable instead of Cat5 even if your current router and networked devices can't take full advantage of it; and get cables (all types, not just Ethernet) that are just a little longer than you need now, because someday you'll rearrange things. Label your cables (at both ends) and "wall wart" power supplies, so you can easily identify the devices they go to; or buy cables in different colors -- Monoprice is a good source for these, and usually less expensive than other places. If you produce a lot of printed pages, consider either switching to a color laser printer or (a better value IMHO) adding an inexpensive monochrome laser to your existing inkjet -- but plan where to put the bigger or additional printer before you buy it. For your next TV, decide on the screen size that's best for the room, then go one size larger; and seriously consider a 4K or higher TV even though the content isn't there yet, because the image is sharper even on ordinary HD programming. I could continue for several pages, but you get the idea.
If you can, carry the plan-ahead concept to your work environment too.