Q: Why do you have/need so many guns?
A: 1) Because I can - this is a free country, due largely to the number of guns owned by the founding generation. I'm just continuing the tradition.
2) Each one is a bit different, sometimes more than a bit. Like a carpenter's tools, each has its place.
3) Many of my guns have some history behind them - I've got a 64-year-old Swiss rifle that helped to deter a Nazi invasion, a Garand that is functionally identical to the main battle rifle that millions of servicemen used in WW2 and a Finnish rifle that was made pre-WW1 and which can consistently put $0.10 rounds of Commie milsurp ammo into a 2-inch circle at 100 yards.
4) It is interesting to take them apart and see how they work. One can learn a lot from doing this, and it is quite enjoyable (it is a HOBBY, after all).
5) Because you never know what you may need, or when.
6) NUNYA - as in none of your business. If I was a criminal, one gun would be more than enough for me to do a LOT of damage. I only have 2 hands, and can only use one gun at a time, so what do you care?
7) To annoy Liberals, especially those in my family. Just like the commercial: AR-15 with scope, $1,200; Remington 700 with scope, $950; Swiss K-31 with Mojo peep sights, $150; Springfield 1911 with Novak sights, trigger job, etc., $1,250; etc. Making a liberal's eyes pop out of his or her sockets and having them nearly break their jaw on the floor when you tell them you feel upset to only have 12 guns, PRICELESS! Even more priceless is when they ask you how many you have, and you start counting on your fingers for a minute or two, and then say, "I don't know, I lost track, but it is somewhere north of 10" or "I could tell you, but then I'd have to take off my shoes."
8) As to need...I have more guns than I need, but far less than I want.