I live in SE PA. Most of the older homes have 1 x 6s for soffits. Some have vents cut into them at either every other or every joist cavity. The NEWER homes are usually soffited w/vinyl, and they simply forgo the 1 x 6s. Instead, they use contiguous vinyl venting which is great.
Just for grins, when I vinyled our house, I started to cut in soffits at every joist cavity (with a Roto-Zip.) By the time I got to the 2nd 1 x 6 soffit, I said #$%@ that - I ripped out the 1 by, and simply J-channeled and installed contiguous soffit. (Under the 1st eaves I did, I simply nailed J-channel and 'covered' my cut-outs.) I guess what I'm saying is it's MUCH better to have contiguous soffits here in the NE.
It was a good 'discussion'. And thanks all for sharing what you know.