It is possible to use a shotgun approach in guestimating an item's value. Certainly such approaches were common in a more innocent time. But in today's litigious society such an attempt is fraught with problems. Not the least of which is a malpractice suit for not using due diligence. As an expert witness I would be very shy of attempting to establish any value of any item without a detailed quantitative and qualitative analysis. An example of a shotgun approach, based on market knowledge, would be that we know most pocket watches, made of base metal and not of antique age would sell in the $100 to $200 range. A problem occurs should anyone ask how we know about a particular watch without specific knowledge. The answer is of course, it is impossible to know or even guess the fair market, or any other value of any item without specific information. Apart from condition, it is necessary to know the manufacture, size and quality and type of movement, materials used in the case i.e.: gold - plated, rolled gold or homogeneous, silver, or basemetal, if the case has a cover (known as a "hunter's" case"), the type of dial, and a case and movement number which confirms approximate place, date and identity of manufacture.