Once upon a time I had many pocketknives, close to a hundred, heck maybe more than a hundred. (Most of them cost at least fifty dollars, some nearly $500.) I finally looked in the mirror and decided that owning a closet full of unused pocketknives was pretty ridiculous. After all I carry just one a day, and after years of acquisition I just had a few favorites. A light nice knife for more formal wear, a heavy duty one for yardwork, another for hunting and then some that have sentimental value like my grandfather's stockman, and then tons of others that never saw the light of day in the closet. I liquidated 90 percent of my collection. I still might buy a new knife, but only as a replacement or upgrade of what I actually use.
Now about pipes... I have six. And plans on getting more. I have an idea, and I'm sure I may even possibly be able to stick to it.
I plan to keep the best ones and get rid of the ones I don't care for as I purchase pipes. I'd like to avoid the accumulation of many pipes and instead create a collection of great pipes, but not more than I will actually use. I envision having a reasonable selection of pipes that suits my life and tastes, but I don't yet know what number of pipes that is... except it is definitely more than six.
I've never smoked a Meerschaum or a churchwarden, so they are on the wish list. I also have a couple less than excellent smoking pipes I picked up from estate sales. Both of those have been languishing on the side of the pipe rack unused in purgatory. I have decided to smoke both of the bad ones next and see if their incarceration has changed their behavior. If not, I will also add a billiard and author pipe to my wish list as replacements and part ways with those. To my eye, the author shape is one of the more appealing pipes, I'd love a great one...at least one that will pass a pipe cleaner. I need a sitting pipe, I'm thinking a sitting billiard would be a nice replacement for the poor smoking billiard I have.
So to summarize my long rambling answer, the appropriate number of pipes one should own is a loosely defined variable that is more than six yet has no clearly defined upper limit.
Grizz