The question we get more than any other at a free measure visit: should I refinish or replace? The honest answer lives in the boards themselves, and three quick tests tell us everything we need.
Test 1: The screw test
We drive a standard 1-5/8-inch drywall screw flush into the face of a board in an inconspicuous spot — a closet, under the edge of a cabinet. The screw's thread begins at 3/4 inch from the tip. If the screw goes flush before the threads fully engage, you have roughly 1/8 inch or more of wood above the tongue — enough for at least one good refinish, sometimes two or three. If the screw pulls flush with thread still exposed, the floor has been sanded close to the tongue and replacement is the better conversation.
Test 2: The moisture reading
We probe three to five spots with a pin-and-probe meter. Readings above 12% in the wood itself flag moisture that will cause a finish to fail or boards to continue moving. Readings above 9% in the subfloor beneath indicate a moisture source that needs to be addressed regardless of whether you refinish or replace. Finishing over an active moisture problem is money wasted.
Test 3: The cup and crown check
Cupped boards (edges high, center low) are usually a sign of bottom moisture — vapor coming up through the subfloor or slab. Crowned boards (center high, edges low) often mean the floor dried too fast after a previous moisture event. Minor cupping sometimes flattens after the moisture source is fixed and the floor is weighted for a season. Severe cupping, boards that have released from the subfloor, or boards with splits and end-checks mean the structure is compromised and sanding will not fix it.
On a typical pre-1960 Minneapolis home with the original 3/4-inch T&G oak, we tell most owners the floor has life in it. We've refinished floors in South Minneapolis craftsmen that were last done in the 1980s and came out looking like the day they were milled. The wood itself is usually the least of the problem.