I always repot, the only time I've re potted and regretted it was during the height of summer, it was too hot for them to recover properly. The cool weather and lower light conditions usually are a help to my trees after a repot but lets see what others have to say.

Usually I tend to avoid a bare root repot this late in the year but I have done it before for strong plants. I have not acquired any plant this late in many years. May be I should visit a nursery here :) If you do repot put in the new plant in a prime spot with warmth and light.

The other option will be to pot it up with a similar mix in a taller pot with ballast at the bottom of the pot. Since I have not bought regular potting mix for a long time I would choose to use "used 511" mix that is a bit more water retentive than fresh mix. Put a overturned smaller pot in the bottom (ballast) and then pot up the rest. Loosen the roots around the root ball if it is bit over grown. Ultimately it is your call since you have to be comfortable with it.

I would lift the root ball out of the pot first and go from there. I received a tree from FW this spring and it looked like it was just put into a new container. I paid more for a larger pot and dirt. The tree could have stayed in the original container this whole growing season, but who was to know if it would have sat on the growing grounds or or be shipped?

Sometimes you find that you don't like the media when inspected too, so that may be a reason to repot. I find almost every plant vendor's media too heavy for my winter conditions. If I don't repot, I usually find the roots are only on the outside perimeter of the pots, due to lack of oxygen inside the mass.

I'm glad you mention that, dbarron. I have a new kumquat that has fruit. It was suggested to me not to repot, so I had to settle for just an inspection of the rootball. I was initially satisfied by seeing roots on the perimeter, and since the rootball stayed intact, I did not investigate further.

But now I am a bit concerned about the interior of the rootball. I did drill extra holes all over the pot, but again, that will likely only help the perimeter of the rootball.