I've owned the earlier model of Panasonic's nose hair and ear hair trimmer for over ten years, and it still works perfectly. I've never had the sharpen the blades. (Can they even be sharpened?) It's easy to clean - just turn it on and run it under water -- the "'Vortex Cleaning System' draws in water from all sides and spins through the trimmer for easy nasal hair trimmer cleaning in seconds." It uses a single AA battery, which lasts months, even for a astonishingly hirsute personage such as myself.
It's regularly $15, but is on sale for $10 on Amazon right now.