Phones, tablets, e-readers, cameras, laptops, TVs, headphones, routers, etc. -- there are a lot of gadgets to buy these days. But when you buy a gadget, it'll inevitably get old. So how often do you update an old gadget? Which devices get updated first?
Despite how often you buy new gadgets, remember that satisfaction from a purchase comes with getting an appropriate amount of mileage from your gear. You can do that by working out a new gadget's true cost over the number of hours you are likely to use it. In my experience, this has made frequent, high-dollar purchases of gadgets I use all the time seem relatively logical and even practical. Likewise, frequent upgrades to my rarely used television and digital single-lens reflex camera would make little sense.
Basically, the more you use something, the more sensible it is to upgrade sooner. The things you use less, don't upgrade and wait it out. Makes sense right! Don't splurge on crap you don't need.
As for me, I wait about two years for my phone, wait around the same timeframe for tablets, double that for laptops (while improving the internals along the way) and wait much longer for a TV. How often do you guys upgrade your gadgets?