I guess I think of this A LOT because it applies to me. I was sober from January 5, 2010 to Thanksgiving Day of 2010...10 months and change. I drank from Thanksgiving Day 2010 to March 26, 2012. During that time, though, not that I deserve a badge, I would say that I maybe got intoxicated 10 times in 16 months. That is not so wonderful, but it is WAAAAAAY better than pre-2010. Does that change my sobriety date? Can I go back and claim 2010 still? No way. But was that 10 months sober very important to me and still is. You betcha.