Worst Hobby In The History

Well said.

I take the view that intelligently-purchased rare coins will, over the long run (>10 years), behave similar to a long-term bond (>10 year maturity).

This perspective excludes transaction fees on both ends.

And the prerequisite to "intelligently-purchased" is extensive experience and long-term engagement (e.g., a dealer or specialist) -- the type who can spot a Maris 18-L or Noe 2-A (or pick your favorite series), and knows what is or isn't a favorable price, and has the capital to available when such opportunities arise.

An interesting way to look at it.

Collecting anything to be rewarding must follow a few rules:

a) You do NOT collect out of fear, rather out of curiosity, interest, and enjoyment.
b) You do not allow your collecting to control you, you must realize when to set a stopping point on collecting. For coins a certain end date or particular goal. At the start it isn't necessary but as time goes on you will desire limitations - it gets boring to simply get something and then throw it into a safe or storage and forget about it --- unless you are collecting from fear which is quite detrimental to your mental health and wealth.
c) Many coins are not necessarily worthless but the time line for them to attain a decent premium is often over generations. Think of common low denomination Roman Empire coins - you can get many for $20 and today those in numismatics think that is undervalued as the days of finding Roman coins easily are over. But this took close to 2,000 years to reach this state of affairs. One reason may be that after Europe's two world wars a good deal pf these coins were simply destroyed. So our copper coated zinc cents which are less durable than the old Roman coppers, will take several generations to attain a decent premium but possibly at a faster rate than the more durable cents from prior to 1982. The lesson is you have to be willing to let go of your collection and be ready to donate. You will likely not liuve to see a premium gained on a good deal of your collection but the intrinsic return will provide a healthy premium (as well as the memory of the find/purchase/auction - one reason to keep records of your acquisitions). To be able to do this you cannot be collecting this from fear.
d) You have to stomach the times you find that the full retail price you paid for something will resell to a dealer at 30% or lessof what you paid. Therefore, if you enjoy what you collect, you will be better able to stomach such losses if you are selling things that have outlived your interest and you simply want some funds to start a new area or reduce and refocus your collection. It may also simply be needed to pay for other costs that are pressing - be thankful you have something at hand to do this!

Finally for those who think they should hold until they die, think about the storage fees. The cost of paying for a secure storage per month - say $200-$300 in one of the more expensive cities of the US, and then consider the cost of after 5 years --- $5,000 - $7,500. You could save yourself most of that money if you prepare for the fact that some of your collelction will sell below or well below the full retail price you paid.

Of course, there's always collecting for the joy of collecting--having a notion where the sideboards are, but still having a blast.

Collecting out of fear is characterized by a few possible behaviours

a) You collect from the anxiety of missing out on the newest item, or not completing something faster, e.g. FOMO.
b) You collect solely to leave an inheritance or to save for retirement to allay your fear of being poor or leaving your heirs destitute and saddled with bills. It is based on a fear of scarcity.
c) You collect soely to one-up others or to prove you are the most knowledgable and best acquirer even though this pursuit may never feel attained nor fulfilled. Collecting becomes a doomed effort to satiate a frail ego.
d) In extreme cases collecting becomes a serious mental health issue - the collecting of things, even if you hate the consequences, is an uncontrollable compulsion. This compulsion is a maladaptive behaviour to some other trauma or stress that never was or has not been completely addressed or resolved. A well-known example of collecting becoming maladaptive and extreme is hoarding. For coins, due to the cost of acquisition and/or the fact they have value (if no premium) to obtain necessities that may be direly needed, it is less common than other items usually hoarded.

*awkwardly glances around room to see if everyone's staring at him*