Wheats are normally best on the young side, but as far as "lasting", they will last months and months. I did a Franziskaner clone for a friend, and after 6 months, although crystal clear it still tastes fine.
And I don't really "condition" wheats. 2 weeks in the fermenter, and a good week of carbing in the keg then start drinking. But maybe your talking bottle conditioning and not aging?