I received my first TENS unit in 1999. It lasted until February. I loved it so much, I took it to a small repair shop, but, surprisingly enough, (not really, but I'm stuck thinking 1999 wasn't that long ago lol), they don't make circuit boards for stuff that old anymore.
Since then, I've gone through SIX! It hurt so much not to have one that I bought two at one time for a backup. The first one died in one day. (It worked one hour.) The next one lasted 3 weeks. The "record-holder" just died. It lasted a whopping five months, and was sold to me by some sales-person who left a card at my pain specialist's office for some company in Florida that sells health-related supplies.
I want a TENS unit that works for at least five years. (Another 17 years would be better. lol) Ooo, ooo, ooo, and to added to that minor little thing, how about one that works well? (I set at full strength.) Too much to ask?