I find myself in this same situation all the time. I always want the latest and greatest. However, with the iPad I have realized it is not necessary at all to upgrade every year, I rocked an iPad mini 2 for almost three years. I only recently replaced my Mini 2 with an iPad mini 3. And that was only because I found an excellent deal on Groupon. I know the Mini 4 was out, but spending $500+ on a device I only use occasionally was insane. The mini 2 is plenty fast enough (Apple still sells it too), and all I really wanted was touch ID and I was able to get that with an iPad mini 3.
Technology is too expensive to always have the best, and sometimes it gets outdated 3 months after you get it. The only device I find myself really needing to upgrade every year is the iPhone…. which probably isn’t necessary but it’s so hard to say no!