Check whether the top is solid or veneered. The veneer on Victorian and Georgian furniture was glued on to a pine base. With age, the pine may shrink at a faster rate than the veneer. This causes the veneer to bubble or lift, involving re-veneering and polishing, which is time consuming and does not always end in a good result. The piece, if not restored well, will look patchy where newer, thinner veneers have replaced the old veneer.
Modern tabletops tend to be made from MDF, ply, or chipboard with paper-thin veneers on the top. This makes trying to remove dents by sanding, dangerous, as there is little room for a mistake. Even with only a light sanding you may go through to the base wood.
Scratches on older furniture with a shellac (French polished) finish have a pale yellow tinge.
If the table has been painted, check the underneath to see if the paint is covering up woodworm, rot or other damage. If it appears to have no damage or other problems, then it could be worth restoring.
Check the table’s height. It should be about 28″ or 31″ high (71cm x 79cm). If it is slightly lower than average, consider fitting castors to raise it’s height. However, they can be expensive and difficult to fit.
Pieces of decorative wooden inlays and marquetry may be missing. Finding replacement inlays is difficult as some of the designs may have been unique to the piece.
If there are castors, check that they are all there and working, as a match can be difficult to find.
Is there any bowing in the boards? It is very difficult to reverse warped wood.
Check the feet and frame for woodworm especially with gate-leg and drop leaf tables. With wooden hinged legs, make sure that the joint does not have woodworm or feel loose.
With marble tops, make sure that there are no cracks and that the corners are not damaged. Marble is costly to replace, as it has to be selected carefully, cut to size and polished.
Brass inlay should not have lifted. It is very difficult to flatten back brass and it could involve carefully removing the inlay, putting it through a press and re-gluing it back into place.