In my case, "need"' has nothing to do with it. I don't "need" all of the shotguns I have either, but sometimes I have a hard time saying "No!" to something that seems interesting, or is unusual or I think I just might like to have without breaking the bank.
I have a "thing" for Marlin Model 90 O/U's. I only had one, a 12 ga., for nearly fifty years. I saw a nice 20 ga. at a good price so I bought it. I liked the way it handled and shot so I bought a 16 ga. Then I thought, why not get a .410, after which I was able to pick up a .22/.410 combo. And so it went.
I now own 16 Model 90's (DT's and ST's) all shooters, in various gauges and and barrel lengths. I did pay $1200 for a .410 Model 90 in 90+% condition and $600 for 16 ga. Model 90 Skeetking (worth at least $1500) at an estate sale in ND. I got all the others for $250-$550 (Paid $550 for a 16 ga. with 26" barrels also in 90+% condition that is now my favorite upland bird gun.)
A few years ago, my dad's friend (then in his 80's) gave me the 16 ga. Springfield-Stevens No. 215 sxs hammer gun that he bought from my dad in 1948 or 1949. I had so much fun shooting it, that when I saw a 16 ga. Tula model B sxs hammer gun for $350 at a gun show, I bought it. Then, I saw a post on the 16 ga.com site about a Husqvarna Model 20 underlever sxs hammer gun. It looked so interesting and unusual that when I found a 16 ga. Model 20 in 60% condition with tight lockup for $150, I bought it. It shoots just fine and it gets a lot of attention at the sporting clays club.