What does this rebus riddle means ?

No matter how little or how much you use me, you change me every month. What am I?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

A man was just doing his job when his suit was torn. Why did he die three minutes later?

What occurs twice in a week, once in a year but never in a day?

There were three women in all the swimming costumes!
One was happy and the other two were sad!
The happy one was crying and the sad ones were smiling.
Why was this?

What does this below rebus puzzle mean?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?