Mike,
First you sould understand that is a very diverse hobby with lots of different "views’ on how to go about doing it.
Don’t let the Tony K’s of the world dictate to you how to buid a model railroad or what to do or not do.
Now a few thoughts on weathering, and on the hobby in general.
IF your goal is to build a realistic, possibly photo-genic layout with realistic scenery, etc, like many you see in MR and RMC, than you most likely want to get into some level of weathering. How much is another question intirely.
For some weathering is a model art form within itself, especailly for many modelers of the current era since there is little or no pride of ownership on todays railroads and stuff is allowed to get in very poor cosmetic condition.
While railroading has always been a dirty business, in many eras past railroads did much more to keep things clean and looking as good as was practical.
Many of us who model these other eras are less likely to weather to extreme degrees, at least not on every piece of equipment. On most lines, the early 50’s was a relatively clean and shinny period, diesels were new, freight cars new or freshly rebuilt with profits from the war, passenger cars too were new or rebuilt/repainted in one last ditch effort to save passenger business.
Back to modeling style and interest for a moment - Many people, some who have responded to your question so far, are more the “collector/runner” type rather than the “scene builder/modeler” type. And that’s fine, everyone should take from this hobby what they enjoy. These folks we tell you not to weather or modify because it will hurt resale value - and they are right! So the question goes to you - do you ever think you would sell your stuff and does “collecting” interest you?
I (and other scene builder/modeler types) generally don’t buy and then resell - I basicly have every model train I ever bought since I was 12, in 1969, when I started buying model trains w