Look beyond the front panel
Check the collar, cuffs, underarms and hem in good light. Turn back pocket openings gently and look at the lining, including the sleeves. A clean-looking exterior can conceal a torn pocket bag or a lining that has worn through at the cuff.
Notice marks and odours without assuming that professional cleaning will remove them all. Ask the seller what is known about the coat's condition and care. If buying online, request photographs of specific areas rather than relying on a single attractive image from a distance.
Test the parts you will use
Fasten buttons and operate the zip carefully through its full travel. Check that belt loops, a removable belt and any detachable parts are present if they matter to the design. A missing ordinary button may be easy to address; matching a distinctive fastening can be more involved.
Try the coat over a realistic layer. Move your arms forward and sit if possible, watching for restriction from either the outer fabric or lining. Do not assume a coat will become comfortable simply because it has already been worn by someone else.
Price the unfinished work
Read the care label and find out what cleaning or repairs are likely to cost before deciding that the asking price is a bargain. A tailor can assess a damaged lining or structural alteration; a cleaner can discuss a difficult mark without guaranteeing its removal.
Consider the coat's overall usefulness after that work. If it needs several uncertain repairs and still does not fit naturally, another piece may be a better choice. Keep the decision anchored in the coat you can actually wear, not an imagined restored version whose cost and feasibility have not been checked.
