In the beginning as a kid in the mid 60s it was all tunable radios so you really did need more than one, at least three running at one time. Crystal scanners, a few would do at one time but in those days there were so many choices and brands and they just kept coming out with newer and better radios. Couldn't help myself.
Then the programmable radios came out and they kept getting better and better and it was so much to listen to, we had a saying in The Newsroom, the more you scan, the less you hear, you didn't want to miss a bank robbery down the street because of a car stop in the next Township.
And you had the trunking radios, then you had the introduction of all the different bands. Then you had digital, then you had all the different types of digital.
God I wish I had a nickel for every radio of every type that I have owned in the last 60 years. I'm down to one in the car listening to about five different things and a couple radios on my desk now. Retired but still don't want to miss anything.