No excuse now with the interweb, model magazines, hobby blogs, shows, swap meets, clubs etc.
But back in the day, before all that , if you didn't go to your local hobby shop (if you had one that kept up with new kits) and check out the shelves or talk to the nice person that ran the place, you were pretty much in the dark.
I remember coming back from the navy in the early seventies, finding quite a gap in my awareness of "New" kits. Years later I discovered I had missed the Aurora Racing Scenes.
I did happen upon a few others just by chance,
Of course a lot of others were just what was on the shelves day to day, at the time.