One thing that I have been asked fairly often is how many pairs of shoes somebody needs to consider themselves a runner. A more frequent question is how many pairs of running shoes do I own. There is no one easy answer to this, and the answer depends on how you train or how competitive you are.
The easy answer to how many shoes you need to be a runner is that you do not need any.
Training barefoot is certainly a viable option, and experienced barefoot runners tend to have stronger feet and are less injury sooner to injury.
The problem, however, is that we start wearing shoes when we are very little, and you need to go into the barefoot mode slowly and carefully. Your feet will be weak due to letting your shoes do most of the work of walking around all day, and running barefoot requests a different stride of us that you may not be used to.
For most runners, the minimum answer for how many shoes you need is one pair of shoes. Most of us will want to wear shoes, and if you are competitive there are definitely advantages to wearing shoes in races. For a casual runner, one pair of shoes will get you out on the roads and can serve you when you are racing.
A more competitive runner, though, is going to want at least two pairs of shoes, and more reasonably three. It is important to rotate your training shoes between each run if you run more than once a day or more than one day in a row. Your feet will sweat, and you really want your shoes to dry completely before wearing them for another run. A competitive runner may also want to have a pair of racing shoes, whether they are lightweight trainers or full on waffles or spikes.
Personally, I tend to have more shoes than that. I actively rotate shoes based on what I've recently worn and where I am running, in addition to the barefoot training that I also do. Where I am running will determine which type of shoe I am going to use based on the following categories:
The first category are my training shoes . These shoes almost always sit on my shelf without I need to go out and do some yard work and they are closest to hand. I very rarely use my trainers any more, although when I did I would often rotate between 4 different pairs of shoes so that even when I was running twice a day every day I'd still have at least 1 day in between having to wear the same pair of shoes.
The second category are my racing shoes , which I wear as my normal training shoe on the roads now.
The third category are my trail shoes, which tend to get wet as most of the trails I run are either muddy or involve crossing open water of some sort. They are lightweight, drain water pretty well, and have an aggressive tread that lets me grip roots and rocks on the technical single track I find myself on.
The fourth category of shoes are my "barefoot" shoes, as silly as that sounds. First, I run barefoot on a regular basis, so obviously those are not actually shoes. But I also have some home-made huaraches (running sandals) and Vibram Five Finger shoes which are very minimal and do not provide any support while helping to prevent me from burning my feet on hot pavement. I will also run on treadmills in just my socks, although this tend to wear them out much faster than normal.
I may be a little over board, but I find that it's useful to always have a pair of dry shoes to run in when I want them. Once my shoes are old and worn out, I donate the ones that may have life left in them as general walking shoes to a local shelter and the rest to the Nike Grind Recycling Project, which recycles old running shoes into tracks and playground surfaces.