I started revolver shooting with a Ruger .45 BH convertible - to shoot up my then-gone G21's stash of .45 ACPs - >11 yr back. I made the mistake of shooting .45 Colts - oops. Bisley BH, BHG Vaquero, .454 SRH, .45 Colt RH, and Puma 24" SS M1892 - all to shoot .45 Colt. Over seven years ago, my wife shocked me with a new 625MG in .45 Colt - life changed. Next - reloading those 2,700+ empties I had amassed - never having touched a reloading press, I bought a new Dillon 550B - just to reload .45 Colt. I like .45 Colt.
I added other calibers - .45 ACP 4" 625-8 & a 629MG for .44 Russians, Specials, & wimpy Magnums. Then - a 6" 66 and 2" 10, the first .357M & .38 Spcl I had ever 'touched'. Skip ahead - all Rugers are gone - and I found a second 625MG in .45 Colt - so I wouldn't wear out my sentimental-favorite first 625MG. By now, I have wimpy .357Ms & .38s, .44 Russians, Specials, & wimpy Magnums, mediocre .45 ACPs, .45 Schofield & Colt, etc. Redundant? You betcha! I can produce the same KE with a variety of bullets/calibers. It's fun. The .45 Colt is real fun. Yeah, I have .45 ARs loaded hotter, but who cares? Look at the MGs - they are just fun!
Is one revolver the 'last one' you should part with. Probably one I haven't mentioned, for just continued shooting fun, - it's my 4" 617! Nostalgia? I'd keep the newer 625MG model - that gift from my wife. I have ~3k rounds, mostly 250gr LRNFP/255gr LSWC, loaded for it - that should last a while.
Bamacisa mentioned the dichotomy - need vs necessity. I wonder which heading his new truck falls under? I think we could take a line from a Sheryl Crowe song - it's not having what you want - but wanting what you have. I am blessed to have all of them (Except the new truck...) - and, for now, I can keep them all, practical or not. I say everyone 'needs' a 25/625 MG in .45 Colt! Of course, I said that about a 4" 617, too - and so it goes!
Stainz
PS I nearly forgot - if it's real historical significance you are after, get you a 29/629 and shoot .44 Russians - they beat the .45 Colt to the marketplace by 2 yr!