sid wrote:

I insulated the outside wall with 1" foam board. My thought is that my
neighbors side of the common wall is heated to at least 60-65F. Do I
really need a lot of insulation on common walls, even if they are
poured ?

If the temperature on both sides of the wall is the same, what's the purpose
of the insulation?

On the other hand, insulation may prove useful for noise abatement.