iPad1 - 1 1/2 yrs. - would have had longer, but was gifted a new 2.
iPad2 - 3 yrs. - I'd still be using this one if I didn't break the screen awhile back.
iPadAir2 - I hope to have it at least 3 yrs., we'll see.
LG G2x - 3 1/2 yrs. - While waiting for T-mobile to get iPhone, then waited longer when news of a larger screen circulated.
iPhone 6 Plus - Well, this one will be either 2 or 4 years, maybe. Not buying both phone and iPad in the same year again, let alone the same month.
Macbook Pro 15" - I've had for 2 years, will keep using it until it no longer does the job, could be a long time.
I ignore the urges to upgrade, they usually involve urges to spend more money than I should. New features are nice, but I usually wait until the piece of tech no longer does what it did in the first place.