In your example, I would look the knife over physically if possible. See how it fits in the hand, balances, points, feels on a board (how the handle and blade interact), if it shows signs of abuse (chips, ripples, bends, rust vs patina), how thick the edge is, how it was sharpened/maintained, that type of stuff. Then I go to fit and finish; if it's something that will be a project knife, this may not matter as much, ie it's an old Sab at a tag sale you want to refurb and put a new handle on.
If it's something I see online, I would try to get more info about it, what steel, rockwell, thickness, weight, look for reviews on the knife, etc. See if the knife is made under any other brands (like some places make blades for 3 or 4 different companies and they are basically the same) and find reviews, etc. People can describe the knife any way they want, what steel, rockwell, etc and most people will have no way to verify. A knife can be made with the best steel possible, but if it was heat treated/tempered incorrectly, that means nothing.
