Depends on the kind of pipe smoker that you are. The old rule of thumb was that a rotation was seven pipes, and that a pipe needed to be rested for 1 day per bowl or a minimum of a week between smokes. If you're an average pipe smoker this would be more than enough to meet your needs.
But today's pipe smoking environment offers a lot more variety (for now) than previous eras. We have a wider range of blends and flavors than in previous times. In response to this, many pipe smokers like to dedicate certain pipes to a specific blend, or a group of blends of similar flavor. The belief is that a briar that has been seasoned with the flavor of a particular blend or near cluster, will do a better job of delivering those flavors when smoked, rather than a pipe whose internals carry scents from a variety of different blends. That would require a wider number of pipes if you enjoy a wider number of blends.
Or, you could go the meerschaum route, in which case the number of pipes needed can be quite small since they don't need breaking in, and tend to be more neutral than briars.
And then, there's the cob, which costs next to nothing, adds a bit of sweetness to the smoke, and doesn't really need babying.
Need is not the same as want. I may need 7 pipes. I may want 700 pipes.
But today's pipe smoking environment offers a lot more variety (for now) than previous eras. We have a wider range of blends and flavors than in previous times. In response to this, many pipe smokers like to dedicate certain pipes to a specific blend, or a group of blends of similar flavor. The belief is that a briar that has been seasoned with the flavor of a particular blend or near cluster, will do a better job of delivering those flavors when smoked, rather than a pipe whose internals carry scents from a variety of different blends. That would require a wider number of pipes if you enjoy a wider number of blends.
Or, you could go the meerschaum route, in which case the number of pipes needed can be quite small since they don't need breaking in, and tend to be more neutral than briars.
And then, there's the cob, which costs next to nothing, adds a bit of sweetness to the smoke, and doesn't really need babying.
Need is not the same as want. I may need 7 pipes. I may want 700 pipes.