I can't believe it's been over six years since I finished ("finished" lol) the shop. I have to say it was one of the best decisions I ever made with regards to the house. Going through Covid with a newborn sucked a lot of the time, and it was nice to have a space I could retreat to when I was (frequently) overstimulated. Since then, I've done a crapload of work in the shop, from maintenance to fabrication (taught myself to TIG and 3D print parts). We've had parties and happy hours at the house where most of the fun stuff happens in the shop. I've helped friends fix their cars. I've spent countless late nights while my kid is asleep tinkering on things in the shop.
We just bought a new place and are slowly moving between spaces. I'm back perusing the forum looking for inspiration, as the new place we bought has just a carport, and I plan on building a shop in its place. I'll start a thread on that separately though.
I've been meaning to come back and update this thread with the good and bad of how I set everything up, to help those of you who're looking at this thread for inspiration or ideas. So, here we go:
Things that have worked out well:
1. Placement - I really like how the shop sits on the lot. Having the garage door visible from the back door, and not walking out into the side of the garage was always a big thing for me. I'm glad I stuck to that. Leaving space between the shop and the fence so I could fit a mower in there worked well. Not that I planned it or could really see how I'd do it differently, but having the door facing south was a plus - that southern exposure light is great.
2. Having it onsite - I'd tossed around the idea of renting a space, but nothing beats the ability to pack up when you're tired and walk inside, or to go outside and break things for a couple hours when the mood hits you.
3. Drainage - We have some underground springs, and I'm at the bottom corner of the block, so we have runoff to deal with, too. Prior to the build the back yard would develop swampy spots and invite a lot of mosquitoes. Tying in the house and garage downspouts and installing a ground drain in the lowest portion between the shop and the hill out back has helped to keep the yard dry. I'm really glad we did that.
4. Roof height - this one's kind of a "no duh" kinda situation, but I'd gone back and forth between 10' and 12' ceiling heights. I ended up with 12.5', and I'm glad I did. Having a full height lift installed allowed me to stand upright under a car (I'm 6'1"), and that's made a world of difference as I've done a ton of jobs that required undercar work.
5. Having a lift - very, very glad I did that. If you have the opportunity to install one and do a lot of work on your cars, it's an invaluable tool. A couple of screw jacks and some tall drain/storage things for oil and coolant were great accessories.
6. Insulation (building/foundation) & HVAC – The air seal/insulation combo with heat and AC made the garage a great space to work in in all weather. It was well worth the extra cost.
7. Door/window location - having the door and only window face the house allowed me to keep track of what was going on, and monitor the ingress points with my security cameras.
8. Matching the siding/style to the house - While the shop is pretty big, especially in relation to the small house, everything looks like it's supposed to be there, and presents really nicely and cohesively.
9. Storage up high on the walls - Installing those shelves allowed me to keep boxes and bins and all manner of **** up off the floor.
10. Doing the permits & electrical myself - I really enjoy learning new things, and valued the experiences of going through the design and permit processes. I'm maybe a little OCD so having things exactly the way I wanted them worked out really well. And the experience I got from doing the electrical (mostly) myself has paid off - I just got done doing a panel/meter base/service disconnect permit/install myself at the new house, and saved myself a **** ton of money. Being my own GC on the shop project allowed me to bid out stuff like insulation which helped me save money, too.
11. Toolbox location - Having the toolbox roughly in the middle of the back wall was a good call. It was close enough to everywhere I worked, and not having to open drawers in front of the car/truck while working on it gave me additional space to work.
12. Power on the lift - Having a quad and a 240 outlet on the lift post was convenient. I could plug in a vacuum, or a welder, (or whatever) centrally in the shop and have room to use either where I needed them.
13. Amenities - having a PC, stereo, and fridge in the garage made it more useful and enjoyable. Heck, the garage was my "office" a lot of the time. Made for some interesting conversations during meetings - I found out a few of my coworkers are car guys

14. Filter fan - A few years ago I welded up a simple frame to mate a box fan to a large HEPA filter. It helped keep the dust down in the garage, and even helped eliminate some odors.
15. Big LED light outside - that dusk to dawn light kept the driveway and street well lit. We don't have a street light near the house unfortunately. I'm glad I did that.
16. Not painting/coating the floor. I had a lot of people try to talk me into this, but I've not once wished I had decking or a floor coating or anything really. Sure, the 4k PSI concrete gets slick if you have wet feet, but meh. As you can tell I'm not a show garage kinda guy

Things I wish I'd done differently:
1. Lift placement - In an effort to save space, I moved the lift as close to the outside wall as I could while still following the manufacturer's requirements for spacing from the edge of the concrete. It's made pulling in and centering cars a pain in the ***. I should have set it up so that you could pull straight in without having to do a 12 point shimmy. That would have eaten some space up on the right side of the garage, but I could have put the workbench along the back wall instead. I also could have walked around the left side of the lift comfortably - that space ended up being material storage, so when the garage was full of **** (thanks somewhat to my wife LOL) I had to move things around to walk comfortably around the lift while I had a car up there.
2. Storage racks, placement of benches - that brings me to the next point. I scored the 4' deep storage racks at a hell of a deal - it came out to $250 for the setup I have once I sold the second rack to a guy who runs a shop and did some work for me. I should have just lined the back wall with 3' deep x 10' or 12' high racks, and built out workbenches on those. I would have had more width in the non-lift bay to open doors and get in/out of cars.
3. Drywall situation - I should never have "finished" the drywall myself. It's just one of those jobs I keep doing but never get all that great at. If I could go back in time, I would have done the walls in OSB and put a 1/4" layer of drywall over top, and have someone else mud it.
4. I should have widened the apron - this was something I didn't think about at all in the design process. I just set the existing apron as a hard point in my head. It made shuffling cars around, and parking the trailer in the yard a pain. I should have widened the apron as much as possible so I could easily pull in/out of both bays.
5. Ceiling vent/air circulation system - having an air-sealed garage is great until you do stinky/fumey things. Any time I pulled a car in or out (especially the non-catalyzed ones) I had to open the window and run the fans to clear out the CO, else my smoke detector would go off. I also never wanted to use brake kleen while the door was shut. I like getting a little buzz from time to time, but not that kinda buzz.
6. Course of brick/knee wall - this is more of a peace of mind thing than anything else. I never had any water reach the bottom of the framing, but in the instance where that ever did happen I'd be worried about the framing getting wet/rotting.
7. The MrCool mini-split sucked. Sure, it was great when it was working. However, I had to replace two blower motors in that damn thing, despite cleaning the filters regularly and having the filter fan setup running nearly constantly. It ran low on coolant at some point, iced up, and dumped water all over my stereo, computer, monitor, and toolbox. A valve eventually failed, and I had it replaced with a better unit. Sure, it saved me some money initially, but it was a "penny wise, pound foolish" decision. Stay away.
8. Could have had a better contractor - I had to ride him to do things the right way, and never did get the proper man door installed. Little things here and there still irk me about the work they did. Sure, I got a great price, but I would have paid more to get things more right.
9. I could have done the cabinets better - more planning and less insistence to use pre-used stuff would have worked better. The lockers for paint storage never really did work that great, for instance.
10. Running water - this is more of a nice to have than a need, but part of me wishes I'd taken the time to plumb water into the shop for a sink. Or maybe a warm water setup for washing cars in the winter.
11. Better bench for the vise - I built a table for the vise out of spare wood and bits, and never quite got it super solid. In retrospect I should have cut up the spare beams I have for the storage rack and made it all metal, and bolted it to the floor.
12. A second lift/quickjack - If I were staying there, I'd move the storage around and put in a four post lift or pick up a maxjack/quickjack sort of setup. Ideally a four post, so I could store more cars inside, and do some work on that side of the bay if needed.
I'll probably think of some more stuff, but those are the big items.