I recently purchased an ASUS GTX 770. I plan to build my gaming PC starting the end of this month or early next month. I will be playing games such as the Crysis trilogy and Mass Effect trilogy on high settings at 1080P. I will also be using this card with Flight Simulator X since I am currently in flight training. Even though the motherboard, CPU, and GPU are overclockable, I don't have any plans to overclock at this time. I am looking at replacing this GPU at the earliest anywhere between zero and six months after the GTX 900 series is released (between 18 months and 2 years from now). But based on any pc gamer's past experience, how long should this card last me when playing games on high settings?
It'll last as long as you want it to. It already won't max out every setting at 1920x1080. You'll have to start lowering settings until you get to a point where you aren't happy with them. I'd expect 3 or 4 years.