Rolling Stock Rules

I'm trying to set some new rules for myself, working on both my present day layout and my 1950's layout. One of them is that rolling stock only goes on the tracks if it's weathered. In the past I've had 95% of the cars and locomotives on the layout remain as they were out of the box. This will also address another issue which is rolling stock accumulation. I have way to many boxes of cars and locomotives that are unweathered and unused. While i do need to build a fleet of modern cars, I have more than enough freight cars for my '50's layout. So it's just a matter of weathering those. And no new modern cars will be purchased unless the previous purchases are weathered. I'm not trying to pigeon hole myself with strict rules though, just trying to take a more methodical, organized approach to my layout building. My most recent weathering attempts are the two cars and locomotive above.