I’d say that, for the vast majority of us, the graphics card is where we sink the greatest amount of money in a PC build (aside from possibly monitors). It’s the beating heart of our gaming, delivering blisteringly fast frame rates while remaining whisper quiet. In terms of upgrades, getting a new graphics card is going to make the greatest difference. It’s the chief component differentiating a bog standard office PC from a gaming monster.
As such, choosing when to upgrade your GPU is a tricky prospect. The conservative option is to wait until it's on its last legs. When it feels like it’s barely going to be able to run the latest games.
Then there’s the opposite end of the spectrum. The power user who always needs the best and they need it right now. You know the sort. They bought a GeForce GTX 980 ti and then they were first in line when the GTX 1080 was announced, already planning their 1080 Ti purchase. For them, making no sacrifices to performance whatever the cost is what it’s all about.
I personally sit somewhere in the middle, happy to pick up a mid/high range graphics card every two years or so. Selling the old one keeps the costs down and I think it strikes a nice balance between price and performance at this tier.
Whatever approach you take, you will always run into the age-old probably of something new being just around the corner. PC tech is fast moving and there's always something better if you just wait. At some point you have to bite the bullet though, so do you prefer to get in their early with a new graphics card family or wait until the prices start dropping? Do you always remain a generation behind to pick up a few bargains?