How to manage sound between duplex units?

[Timothy Vance]

I own a two-story duplex that was originally built in 1938. One unit occupies the entire 2nd floor, and the other unit occupies the entire 1st floor. I'm househacking now. I try to be quiet for my tenants above me, and my tenants above me are quiet and respectful for me too, but I plan on eventually moving out. 

My question is: How do y'all manage sound between units? The walls (or in this case, floors) are very thin and you can hear quite a bit.

How much of a drawback is this? 

Will I have to provide discounted rent in order to keep future tenants happy?

Has anyone had luck tearing out the floor, securing loose floor beams, and installing sound insulating materials? I'm not trying to eliminate all sound, which would be impossible, but at least eliminate being able to hear talking, TV, and radio.

Any other recommendations?

Thanks, y'all!