There are few delights more uplifting to the philatelist then the discovery of something unusual or valuable that has lain hidden for months or years in one’s own stockbooks or envelopes of alleged duplicates.

Such a discovery is often accompanied in my own case by incredulity that as a seasoned collector I could have overlooked such a thing after having owned it for years! But it happens.

There are certain things you can do which make it more likely that you, too, can have a “eureka moment.”  A few suggestions follow, discussing how to increase the odds of a good find, whether it’s in your own duplicate material or in a dealer’s stock.

If you collect according to a specialized catalog, it is worth re-reading such a catalog, or parts of the catalog, or monographs on a specialized subject area. Unless you have a photographic memory, you tend to forget a lot of detail, and revisiting the written authorities often refreshes or puts a search into focus.  

A few pocket-sized tools are a big help at shows.

Second, there is no substitute for a good magnifier used in a good light. Magnification of 8x to 10x is plenty for scanning alleged duplicates. You may wish to keep an instrument like a binocular microscope in some cases, but that is normally more power than is necessary for scanning purposes. And small pocket magnifiers may not work because they do not blow up the view enough or the field is too small.

Third, if you have already been fortunate enough to find the rare shade, perforation variety or plate flaw once, you can increase your odds of finding more of them by carrying a specimen book with you to shows or trips to dealers. A side-by-side comparison is the best way to eliminate forgeries or a stamp that closely imitates what you may be looking for. 

Fourth, it is not a bad idea to carry a pocket ultraviolet lamp to shows. I have forgotten to do this sometimes, and have been unpleasantly surprised later to find defects in an item that I would not have bought if I had looked at it under UV light.  

Fifth, know your dealer. The vast majority of dealers in the stamp business are knowledgeable and honest.  If you have doubts, arrange for highly valuable items to be bought on condition of expertization by a recognized authority. 

These are just a few things to keep in mind. I hope one or more of them is helpful to you.

Happy hunting!