I was in a LHBS recently, mostly because I was in that area and need a couple minor items. I was told by the owner that he doesn't carry lactic acid anymore since 5.2 came out and everyone is using that now.
A helper in the shop also told me the Bevflex 200 3/16" tubing is for gas, not for liquid. So all this time I've been using the wrong tubing on my 6 tap kegerator.
And finally I remember years ago him telling me the O2 absorbing bottle caps was a huge marketing ploy...so why does he sell them?
Moral of the story...know your facts because your customers are not as dumb as one would think.