|I've always used the little wire needle threaders -- you know, the kind that come three in a pack. They get broken, lost, misplaced, and bent in weird ways.
My last threader was severely twisted -- such that I couldn't easily fit it into the needle hole on my machine. In desperation, I picked up a pair of reading glasses (that I had mistakenly bought one power too strong) to help me see the hole. I was surprised to find the reading glasses magnified the needle hole so much that I could easily slip the thread through by hand without resorting to the needle threader!
I no longer try to keep track of those pesky needle threaders. Instead, I keep a pair of reading glasses (1 diopter size too strong) close by my machine -- works much, much better!
By the way -- I only use this for threading my machine's needle. I've learned the secret for hand needles is to use tapestry needles -- the holes are so long that I can thread them without any eyesight assistance at all!