Cambre
I'm with you, the power fold deck definitely makes it very tempting to keep the blades at maximum performance! I have been known to take a file to my blades from time to time I don't know the brand of file but it works very well with my factory Grasshopper blades, it does take a reasonable bite of metal without using much force. I did buy the best file I could find in Menards it may be Stanley I'm not sure.
It takes me a few hours to mow my property and I sharpen every few mowing's although I do use a Magna Matic blade sharpener, by keeping after them it really doesn't take but a single pass or two after which I may clean them up with the file. Your right I can tell the difference in the lawn by keeping the blades fresh but I would have to admit without the power fold deck it would be quite a bit tougher.
Never feel guilty about wanting to have the best cut in the neighborhood I realize the lawn care guys can't spend the time us amateurs do taking care of blades but that's a perk of only mowing our own acreage's.