I would doubt that the vine is particularly old as the trunk isn't that big and it would seem that two in such a small space is sort of overkill.

I find myself with a bunch of questions that need to be considered before a decision can be made:
Why did the consultant want it removed?
Is it damaging anything currently? It seems like you keep it pretty tightly pruned from what you wrote in your blog.
Do you like it?
What function does it serve? Beauty, obviously, but privacy or shade or . . . ?
Is it wandering, such as coming up in your lawn or crawling through your foundation? Is it scattering seed around and being invasive either in your yard or other yards or nearby woodlands?

Hi,
Thanks for responding He said wisterias should be allowed to ramble in a much bigger space, like on a grape arbor. It's not affecting anything structurally. It does provide cover for when I sit on the porch. When I first moved in it was just plopped on the ground and filled up the whole space. I used to put hanging baskets on the porch, which I can't do now because they'd be blocked by the wisteria.

I love it when it blooms. It smells great. I'm just always hesitant to remove something that's been there a long time. Plus I'm not sure what to do about getting a more secure support for it.

If it isn't seeding everywhere and you don't mind doing the heavy pruning, I'd leave it since you like it. You could always build a heavy duty pressure treated structure for it if what you have there already isn't working. Some folks grow them like trees. Look at Claire's and Evonne's in the link below or kt's in this thread:
http://forums.gardenweb.com/forums/load/neweng/msg041725213986.html

So you really can prune it however you like to please yourself. If it gets out of hand at some point you can remove it, with a large saw and some brushkiller on the remaining roots, though it may need repeat removal to get it completely gone.

Here is a link that might be useful: wisteria trees