For some people selling their coins is an easy decision. The motivation varies from no interest in the coins, decluttering the house, or possibly a financial need of some sort. Or perhaps a combination of the 3. Others, that have collected or inherited a collection that don't necessarily want to sell, but it is still important to keep abreast of what the coin market is doing relative to the type of collection that you have. Why would someone want to know the value of their collection if they don't want to liquidate their collection? There are several reasons:
* One may possible need recourses in the case of an emergency in the future. Knowing a range of value can help evaluate various options.
* Values of coins should dictate how the coins are stored. Having a few hundred wheat pennies, buffalo nickels, or 90% junk silver in circulated condition is different than having a valuable high grade rare coin. You can really hurt the value of a coin by how it is stored, if its rare. I saw a collection recently where the coins were stored in little mantilla type envelopes. There were some nicer coins in the collection, but the coins had been damaged by the dye in the envelopes. There was a yellowish tint on the coins that caused significant damage. In the coin world we call it "environmental damage". High grade coins should also not be in coin books. My choice would be a non-PVC flip, or a "airtight" An airtight is a hard plastic casing that the coin in placed in and then snapped shut. Important note: Don't attempt to clean a dirty coin. A person has to be extremely careful when addressing a coin that is dirty. Dirt doesn't always mean damage.
* How will your heirs know what you have, if you don't tell them? I'm sure many a valuable coin has ended up in a pawn shop and sold for a fraction of the value. Identifying valuable coins could be a valuable gift in it of itself. Providing a detailed list and approximate values are an absolute must when passing a collection. If you wanted to take things a bit further, you could actually provide your heirs with trusted contact, in case they would like to sell the collection. It's a way for you to be involved in how things are done after you are gone. Also selling those coins in Denver is one thing, but what if your heir lives in a different state or country. The more information you can provide, the better. You shouldn't leave things to chance.
Value can impact many things as it pertains to your collection. It can also simply satisfy some curiosity. Maybe you have had your coins for a long time and you just wan to gather more information. The more information you have, the better.