use vs usage

Hello all,

I am wondering whether there is a difference between the use of the words use and usage. I believe that their meaning is the same and i have heard people using them interchangeably. However, there are others who avoid using the word usage and i was wondering whether this due to a difference in meaning or a language dependent thing (e.g. American english vs british english)

thanks a lot in advance!

Not a teacher.
I think "use" means the state of being used while "usage" means the way, the fact, the amount of sth being used

interesting.. but i am afraid it doesn't answer clearly of how/when should i use it...

For example:The software is designed for use in school.
They don't know the software's usage.
I simply understand that "usage" is used to emphasize the characteristics of sth and "use" is used to talk about whether sth is being used.