As always Steve offers the practical viewpoint that should be kept in mind. In the case of my shop, I'm 54 and expect to "retire" in 10 or 12 years. I fully expect that I will be doing some various things in the shop at that point to make a living since I really don't expect to have a Million bucks in the retirement funds by then, so I expect I will have to do a few things to supplement my retirement income.
I have watched my Dad since he retired 20 years ago say every year that he is going to build a shop. He buys Hondas at the auction, gets them in shape and sells them. He farms out most of the body work, but still does quite a bit in his garage. I don't want to look up after 20 years and wish I had built a more adequate facility when I could have.
Okay Cap'n. It looks we will need to all have a copy of AutoCad to get into this.
I would make a few comments about the shop. I put a walking beam down the middle of my shop. It's handy as a pocket on a shirt. I can easily pull an engine and move the chain hoist forward to lower the engine and mount it on an engine stand. It also is handy for supporting an engine while pulling a transmission. It also is useful for unloading heavy equipment from the back of your pickup. Just lift the equipment and drive the truck out from under it.
Also I have my compressor in an out of the way place with pipe running up and teed off to put a pigtail hose in three places in the shop from up above. I also have a long hose I can reach about fifty feet out into the driveway.
It's probably obvious, but put the parts washer next to the work bench. Make sure the workbench is plenty stout enough for a good sized vise. Mount the vise on the opposite end of the bench from the parts washer.
Have a great day,
PS: I wish I were close enough to Gainsville for Steve to keep my buggies going. LB