Sooner the better- the longer you wait the more interest is accrued. I paid mine off first year and it's a wonderful feeling to not pay double in 30 years with the interest.

With that said...

If you're not going to be here in 30 years.. or if you sell to move to another home. best to not pay it off as the bond follows the house not the owner.

I personally am staying in this home (no exceptions)