Nothing looks disastrous by itself; it’s the number of loose ends. I’m comparing a 480 sq ft retail unit with a similarly priced condo in Boston. The retail space appears simpler to maintain, while the condo seems to offer more control but could bring larger irregular costs. I’m modelling energy performance, insurance, energy use and resale liquidity. What costs tend to emerge after year one, and what should be on a practical pre-purchase checklist?