I don't know how to put this in a question so I'll give an example.
As we all know if you fast on the day of Arafat sins from the previous year and the next year is gone.
So here is the example A muslim man fast on the day of Arafat on 2011 (meaning no sins for him on 2010 & 2012) and then in 2012 he wants to taste alcohol and he tries it even though he knew it is haram and a huge sin, he still tried it because he is sin free that year. So by drinking alcohol on purpose and not ask for forgiveness, is this a sin or not. I think it isn't because he did fast on the day of Arafat on the last year, but I'm not sure.
And FYI this man^^^ is not me it was just an example. And I was just curious