How much is too much?

My roommate says that I have too many pairs of shoes. I think I need at least 2 more pairs (one more for work and one for going out).

So the question is how many pairs of shoes exceeds the acceptable level of shoes for man?

I currently have 13 pairs. Discuss.

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Update: My roommate remarked on this topic when I moved the entire collection from my room to the hallway so I could thoroughly vacuum. The inventory is as such: 2 Pairs Black Dress Shoes, 2 Pairs Brown Dress Shoes, 1 Business-Casual Black, 1 Pair Brown Pumas, 2 Pairs of Basketball shoes, 1 pair low-rise Jordans, 1 pair of running shoes, 2 Pairs of sandals, and slippers.

I wear them all