My old shop was a 3 car garage, with a 16' wide and an 8' wide door, with a 20' extension on the back, making it a 30x40 workshop. 8' ceiling. In it, I built an "L" shaped wall, dividing the 16' door space from the 8' door space, traveling 1/2 way towards the back, and then making the L to effectively square off the 16' door "2-car garage" area to park and store stock in (~400 sq ft), leaving the larger "L" work area (800 sq ft) for tools and working. The L shaped wall held a ton of electrical, jigs, moldings, cabinets, etc. It was very useful, but in some ways limiting, mostly likely due to the number of machines I tried to cram in there.
My new shop is a 28 year old 30X40 barn with a 12' ceiling. Free span - no posts, no walls.
Back when I was contemplating building and designing a timber frame shop, I frowned at the idea of posts. But, alas, as I am setting up this "free span" shop, I find myself adding posts to accommodate electrical drops and duct collection piping/hoses.
So, I am now in the camp that posts are a good thing. I guess you can have too many posts, but the three that I have installed are certainly non-obtrusive and quite functional.
Do you have a free span shop? What do you do with electrical and dust collection? I have too many machines to just be able to put them around the perimeter walls.
Todd