For the sake of all of us, show your devices some love. Get really-really into them. Reuse them. Repair them if they're broken. Creatively repurpose them (this activity is also known as 'hacking'). If you can't, give them to someone who can do that for you, we're always looking for a job (and things to do).
Perhaps you know a "digital native tech shaman" (heh) in your family. Don't forget to pay them!
Upgrade only as needed, preferably gradually, and don't throw out the old stuff: you don't know when you need a spare or your little cousin needs one, certainly for school, pinky promise.
Don't upgrade often, don't jump on new and shiny. Moore's law does not dictate you to buy into every iteration. In fact, skip a couple of generations. It's better to be truly amazed by your next big upgrade, than jumping one and getting only 'meh.' performance growth. Learn the benefits of delayed gratification, and stick to what you already have.
When you DO the big upgrade, treat it an investment it is. Factor in the ownership costs like repairs. If one device is unrepairable but cheaper and the other one is easily repairable with parts available, but the price tag is higher, take the latter one, for it is truly the cheaper option: it will last you a good while.
Use FOSS. In fact, default to it. You don't need to necessarily become a Stallmanite, use the right tool for the job, sure, but if you aren't giving a FOSS solution an honest try before resorting to proprietary products, you're doing yourself a great disservice by robbing yourself of choice. Trust me, you'll be amazed with things you can do and how much of your needs you can cover with just about any modern GNU/Linux distro. I've come to use it almost exclusively. And it's free! And it's hackable! It just takes some getting used to.
When you DO the big upgrade, treat it an investment it is. Factor in the ownership costs like repairs. If one device is unrepairable but cheaper and the other one is easily repairable with parts available, but the price tag is higher, take the latter one, for it is truly the cheaper option: it will last you a good while.