oggyphillips :
To be honest, I don't need to upgrade, I just love buying new parts for myself. I'm addicted ahaha
Nothing wrong with that....it's your money! However I only upgrade when I need to, like going from 1080p to 1440p. The 1080Ti is way overkill for you though.
Under normal pricing, a 1080 is $550USD and 1080Ti $750USD. At 1080p resolution, the GTX 1080Ti is only between 10-20% faster than a GTX 1080 depending on game but costs 37% more. However at 1440p the gap widens between the 1080Ti and 1080 making it closer to worth the increased price/performance ratio (something I watch closely). Case in point, BF1:
1080p: GTX 1080 -> 145fps, GTX 1080Ti -> 161FPS
1440p: GTX 1080 -> 98fps, GTX 1080Ti -> 131FPS...