They’re built for heavy use and have faster drying times—usually 30–45 minutes—without needing major electrical changes.If you’re up for a bigger investment, adding extra stackable units in the garage could be a great long-term fix, though it’ll mean some electrical work and setting up proper ventilation.I’d probably go for the commercial upgrade in your current space first—it’s quicker and might solve the bottleneck right away.

We re-piped the plumbing with Pex, installed new toilets, new showers, new hoses & fixtures.

They're cheap to purchase/install too. 

Quote from @Alan Mills: Got an inspection objection back with something I’ve not seen on my other rehab’s (this is a Colorado property):“The seller agrees to have a licensed plumber install external sewer cleanouts per city code and scope the sewer line ensuring its integrity.”This was a full interior/gut rehab and almost everything is brand new.

You might find that installing a mini-split system, properly insulating, and ensuring the finishes match the main home’s quality will make a difference in how the appraiser views it.

How many are you installing a year?

Still need cabinets vanities counters installed, floors done, drywall hung and finished.

If so, were permits pulled & were they installed by a professional5.Are any of the homes rented to students6.Is there a flat roof7.are there asbestos shingles8.

Wiring for special purpose equipment would be like having to install 250V wiring to run a commercial walk-in freezer. 

Stairs are the only way to get in, no grab rails in the bathroom, ramps that are too steep, etc.From what I've read, all commercial businesses/buildings (including ones before the ADA was passed) have to comply with the rules, unless it would be outrageously tough to fix (like installing an elevator in an already built building).Are all these local business just not complying and taking the risk, or am I missing something?