Mudlark, I bought my pitch pipes when I got my guitar, and always tuned by ear. Never bothered me until the first time I went to a folk session, tuned to the pitch-pipes and then found everyone else was in a different key to me by a quarter-tone or so! It took me several months to realise that the problem was not with me tuning by ear, it was that the pitch pipes were totally shot!

If you can tune by ear, get a harmonica and use that as a reference tone. Pitch pipes are usually cheap and nasty, whereas a harmonica is designed to be played as an instrument and therefore has to hold its tuning pretty well. You don't need to be able to play the harmonica, you just need to be able to blow down a single hole and tune your instrument to that. And you can check that your harmonica's still in tune by blowing down all the holes at once and checking you still get an OK-sounding chord, since it's unlikely that all the reeds will go out of tune by exactly the same amount.

Graham.