Valuing A Stamp Collection

I'm trying to value some parts of a collection that I inherited, that I might like to eventually sell.
I know that Scott CV, is a retail value, and resale value, if I'd like to sell will be much less.
Some questions, value of used stamps. I have many, many used stamps, old and newer, but mostly modern, ex. Israeli tabs, japanese, british empire, varied countries, whose scott catalog values of used, many times is virtually equal to the mint catalog value. Is this really possible in modern stamps, that the used value is equal to a MNH stamp?
And if I'm valuing for example a mint and used Japanese collection, can I actually use these used catalog values, along with mint values as a barometer to the total value of the collection?


*** Moved by Staff to a more appropriate forum. ***

Yes. It it really possible for modern a used stamp to have the same catalog value as a MNH version.

One thing to remember is that, whilst catalogues must assign a price or a value, stamps assigned the lowest prices or values are, in fact, close to valueless in the real world. Most stamps are penny stamps.

A reasonable rule of thumb is to a resale assume you will get 5% of catalogue value for full sets unmounted mint post-1945 (unless you have known major errors) and 15% of catalogue value for everything else. "Classic" stamps of high initial catalogue value, especially full sets in good condition and well-centered, can get up to 40% catalogue value.

Some countries have a premium for types of stamps (e.g. Germany for unmounted mint "classics"), and some countries have a better market for certain types of stamp than others. Smaller auction houses in the UK, for example, sell many country collections on leaves, but this market may be different in another country.

Catalogue values are set by dealers, so those are the prices they wish to receive to cover their inventory, web sites, advertising, staffing, property rental/taxes, light, heat and power costs.

For example a used modern stamp in The Unitrade Specialized Catalogue of Canadian Stamps is valued no lower that 20 cents. That means that if you were to buy only one used stamp from a dealer, she/he would want the full 20 cents. Buying multiples of single used modern stamps would allow the dealer to significantly reduce the total selling price of the lot.

Catalogue pricing methods vary by catalog maker. Yes some makes seem more interested in supporting a diminishing "traditional" dealer model meaning it is not "market pricing" but subsidized pricing model. Dealers that price at catalog are not pricing by market. For some this leads to disappointment when the dealer would only pay a fraction of what the person paid for it.

Also keep in mind that catalog values are for "very fine" examples. Off centered and damaged stamps sell for a small fraction of catalog value if they can even be sold.