I've recently finished a project that requires continuous air flow (24/7), and I'm using a 12v fan for this, does anyone know if it is safe to leave a DC fan on continuously and if running it at a lower voltage affects the lifetime of the fan? (It spins up fine and it's not likely to get obstructed)

 

It will run but not move nearly as much air as it is rated for. I don't think its life will be shortened (I suspect it may last longer) but it would be nice to hear from a fan expert.