My sobriety date is important to me, it was a day that changed my life. I don't count my time, per se, but that date will be etched in my head forever.
If I ever purposefully drank alcohol, even a swallow, I would change my date. About the NA beer thing, I think it's nonsensical for an alcoholic to go there since it does in fact contain alcohol (and all the other psychological triggers that go with it, the bottle, the smell, the taste, etc), but I'm only in charge of my own recovery.