Years ago, when I first started smoking a pipe, after a bit of time, I was getting a very strange taste out of my one good pipe, a City Deluxe from Fred Diebel in Kansas City, I brought the pipe to Fred to ask him why it was developing this funny taste, and he asked me how many times a day I was smoking it. That provided the answer, because clearly the pipe was being over smoked. The pipe was so awesome when I initially received it, ($10 as a gift from a girlfriend--big bucks in 1960 dollars,) that I laid my other two cheap pipes aside in favor of this one. Fred told me to rotate and also to pick up one or two corncobs to increase my rotation at a very inexpensive rate. As an undergraduate, the economy made sense to me, but it still makes sense to have a rotation even if you're not a starving undergraduate.
I recall reading not too long ago of a discussion between one of our American pipe greats with one of the prominent European pipe carvers. I forget the names, but the American may have been Fred Hanna. At any rate, our interlocutor asked the European how many pipes he had in his rotation and the response was five. Really, that's all you need for a good solid rotation. However since my years as a starving undergraduate, I have acquired a few more pipes than that, and they are pipes of varying quality, including some from Pablo Becker, and some of lesser reputation. I now have 93 pipes in my active rotation, including a few custom made pipes and carved originals that are truly beautiful to look at. And here's the thing, they don't smoke any better then some basket pipes that I've picked up at Peretti's – why, because a basket pipe at Peretti's is fundamentally a very good pipe, and you won't go wrong with it. I also have a few pipes that I haven't yet initiated, including an Israeli made Alpha, two Connoisseurs, a Claudio Cavicchi, and some others of good repute that have not yet made it into the stable.
And here's the thing: all that represents the experience of 54 years smoking a pipe, years of saving to pick up the pipe I wanted, sometimes coming by one in varying ways, but they have all been years of unmitigated pleasure sitting down, puffing slowly away, enjoying one of life's truly great pleasures. Yes, there's certainly a good bit of PAD mixed in with that, but that's not at all a bad thing.
I'll conclude with this thought: if you have five pipes, then you have a legitimate rotation, and you can alternate amongst your pipes so that you can be assured of a clean fresh smoke with every bowl. Beyond that it becomes collecting, and here you'll have to exercise a bit of forethought and judgment--if what you want is good smokers, you can do that fairly I expensively. I might recommend joining the NASPC, as I and many others have done. As many pipes as you have --enjoy them. It's a hobby after all.