1. Buy Your Tech at the Right Time: Some manufacturers, like Apple, stick to a somewhat predictable upgrade cycle. iPhones and iPads get updated once a year. The dates are well known. iPads are released each March and iPhones each October. If the dates vary, tech news sources will likely post the upcoming dates months in advance. The right time to buy your tech is a couple of weeks after it's first released. That way, it lets the manufacturer iron out the kinks that new tech usually has.
For those in need of a visual aid, check out this chart outlining "Knowing Exactly the Right Time to Buy a New Mac, iPhone or iPad"
3. Carrier Contract Features: Smartphones get regular updates, and changing them to a new one will usually make a difference to most people, as they use these devices a lot. That being said, most carriers have an agreement to take back some of your tech if you upgrade to a newer version on the same contract. Our carrier offers significant rebates when we do this, which is why upgrading our smartphone won't be problematic.
4. Highest Spec Devices: As a rule, I always buy the highest-spec devices available. If there is a 64GB version of a phone or a tablet available, I get it. The reasoning behind this is that these devices keep their value slightly longer than the ones with lower spec, allowing you to benefit in the long run.
5. Always Sell Your Device Before Upgrading: Upgrading tech is like an itch that can't be reached until you purchase that new device. It's hard to resist, but it makes a lot of sense to sell your old device before you buy a new one. It's not easy to adapt to life without it. I had to spend about 2 weeks without an iPad and it was problematic since I use a tablet for some work-related tasks.