Graphics Card Help

Seeing as my original post didn't post up I just wanted to ask if this was alright:

My GTX 970 while idle usually runs at 40-42 degrees celsius and I wanted to know if that was fine. While running high games it usually goes up to 65 and I checked this using precision x and while running ultra settings it usually hits 73-75.

I was going to ask if it was alright to change the fan curve to run at around 2-3% constantly even when idle and to increase the fan speed at high temps. Would this damage the graphics cards lifespan in any way?
 
So if I was to leave the fans constantly on at around 20%, would anything happen to the lifespan of the graphics card. Cause I was reading around and was told that the fans should be kept on automatic in order to reduce the chance of the fans failing but while idle for me, it just goes up too high.