I found an old sonicare toothbrush here, and I want to start using it but I want to get some new attachments (ie brushes) for it. Are the attachments universal for all sonicare toothbrushes or do you need to get different kinds for different brushes? I suppose I could just go to walmart or Target and buy some attachments and test them out, but if they don’t work I don’t know if walmart would want to accept a used toothbrush for a refund.
Mine is years old and the attachments sold today still work with mine. They are called "Standard’ when I buy them…though they do make a smaller brush head for those hard to reach areas…
Buy 2 at a time. Cheaper that way.
Sonicare has two different models, the Standard and the Elite, and the replacement heads are not interchangeable.
Pardon me, that should be Advance and Elite.
FYI I’ve used a Sonicare for years, and swear by it. As to the OP, I don’t know.
They do sell the handle (at least I bought one) that dosen’t beep every thirty seconds. THAT is a handy feature.
(All my teeth ((and metal)) at 64)! 
I was thinking of getting one (I have the bad habit of brushing/sawing across with regular toothbrushes, too hard, and it’s ruining my exterior fillings), and this thread is the impetus.
Thanks for that link, Fear.