That's good advice! I'm 72 now and I'd hate to even think about building another shop.
I tried to plan to avoid moving things. It was mostly successful. I had bought the major tools before I built the shop (I was afraid I might be too broke later) so I knew the footprints and infeed-outfeed space needed. I made plan after plan until I was satisfied. I ended up leaving one bandsaw in the garage and the third big lathe in a storage building unless needed. By planning before construction I could easily do things like position some double doors to allow for longer infeed/outfeed on the table saw if needed. For someone in the planning stage, I highly recommend this method: make a scale drawing and scale cutouts from paper. This is part of one plan, in progress, still sliding things around:
layout_paper_2.jpg
I also made some paper circles representing the minimum and desired passage space between tools, bench, etc. and "walked" them through the candidate plans. When I got things finalized I taped down the paper slips and made a drawing. I did similar planning for the electrical outlets, lights, and air compressor lines, long before I started working putting up the building. Making these plans even helped me decide where to put some of the interior walls.
Although I am well experienced in 2D and 3D drawing/modeling, I found it easier and quicker to do it the old way with paper cutouts.
As mentioned elsewhere, my shop is 24x62. The length was limited by the site but to this day I wish I had made it 30' wide instead of 24. That wouldn't have cost much more.
shop_floorplan.jpg
I did make some minor changes as I changed directions (e.g., put in incubators for peacocks/guineas in a corner of the main shop and used what is labeled as maintenance bays primarily for raising birds, turning wood storage, little machine shop, and fluids and filters for equipment maintenance), but the basic planning has mostly worked well. The drum sander is on wheels but the cabinet saw hasn't been budged even an inch since set into place. One thing I did change my mind about was the number and placement of windows. I realized that wall space was more valuable to me than the natural light and view so I eliminated several windows. It's just a few steps to where I can see the barn, llamas, and bird pens. I have daylight fixtures so bright one visitor said he needed sun glasses. Works for me.
JKJ