Got some 280x's still going for almost 3 years 24/7 temp 80 degrees 70% fan. Fans did stiffen up after about 2 years... I just spray some wd40 in them carefully when it happens and they are good as new again!

Ps. Wd40 is not recommended I belive machine oil is but... I've not had any problems so far... just made sure I didn't use too much so it would leak or get it on the gpu board.