How to Avoid Common Colds?

I was getting a bit of a scratchy throat. I don't know if this is a normal thing, but when I was in my like late teens, early 20s, I was getting sick more often and usually for longer periods. Now let's say 10 years since then it feels like if I get sick, it's usually much more mild thing. And maybe that's the thing because also people who are who are elderly, they usually don't get like common colds. That's supposedly the science. Yeah, you build up some sort of immunity against this. It's not really something you can fully avoid right? We're exposed to a lot of things.