Needed a new bra, but didn't have time to go anywhere with a decent fitting service, so I searched for threads on bra fitting on MN, bookmarked them on the iPhone & went off to Tesco's, which does have a changing room and 3G coverage, so I could check up on all the fitting tips in peace.
Result - I'm a 34DD, not a 38C and I have two beautifully fitting comfortable bras.