It depends on who you ask. It depends on what religion you are approaching this from. It also depends on what type of sins. I hope other people will provide there own answers (different views). But I am Agnostic (the view that the existence or non-existence of any deity is unknown and possibly unknowable).
I say you do not have to answer to God.
But as a memeber of society, if you did something like murder without cause or child molestaion, you should fry.
If you did something silly like say the lords name in vain, forget to pray on time, did not attend church, cheated on taxes, etc I would not worry about it.
People like to build up guilt for some reason. Organized Relion takes advantage of this.