I feel your frustration! A little embarrassed to say it, but hey, I burn out a lot of motors
However, one or two toys that I bought 3 years ago are still buzzing away, while things I've bought in the last few months have already sputtered out. I buy Lelo (which are so good when they're new, but still the same longevity issues - a good thing that they are guaranteed, as they have sent me a few replacements) and other quality items, some of the cheaper ones have died within days. Occasionally I find some no name piece of plastic in a pretty box that rocks my world, though.
I agree with other poster's advice - buy from a company that will back their products, as it's generally hit or miss. I've got friends at Good Vibrations, they always do right by me.
~Mme X~