I have two 1960s Savage bolt action .22s same action different calibers-- a Model 73 .22 lr, conventional stock, that was my son's first gun, and a Model 63KM .22 mag, safety key lock, Mannlicher stock, that I bought because my sister gave me a cleaning kit, pistol case and a box of .22 magnum ammo for Christmas when I did not have a gun in .22 mag caliber and I did not say anything to her but thanked her. I then told my wife that now I was obligated to buy a .22 mag rifle.
If you check with Numrich Arms Gun Parts, all replacement parts are the same on the Savage/Stevens 63/73 series except for the barrels and the stocks. (BTW on this model the factory orginal extractors all seem to break, but the replacement part extractors all seem to be properly heat treated.)
I have two Mosin Nagants -- a "sporterized" Type 53 carbine and an as-refurbished and issued 91/30 with octagon receiver. One intended for bad weather hunting, and one for vintage military matches, both as examples of their type--civilianized army rifle hunter, and military issue WWII battle rifle.
I have a CVA Bobcat .50 cal muzzleloader that I replaced the sights and used in black powder matches. That's the model WalMart sold for 69.95, and when they had one at the after-season 2006 sale for 29.95 I bought it for spare parts. The first is still in running condition twelve years later and the second was testfired, cleaned, and put back in the box Just In Case.
Why own more than one of the same? Sentimental reasons, one for keepsake one for practical use, historical reasons, spare parts or spare gun w/o cross training, slight differences for curio interest. Why not own more than one of the same?