You will know right away because obviously hes going to move on and act like you and him/her never existed. If he/she weren't over you at least they would do something showing you that they aren't over you.
If he says he needs time because his ex is giving him grief then that means he is totally NOT over his ex
She may just be curious or she may not have been totally over him.
you know that your over him/her if you realy dont think about them a lot.
you know there over you if they flirt or date other guys
I've had that problem before, i hope you can get an idea out of this....... i went out with a new guy i liked and broke up with him for my ex, from then on i have not talked to my ex because he was mad he was my second, and the "new" crush kept being mean to me becasuse i broke up with him for someone i said i was "totally over" so i would say wait until you know you are completley over your ex first then get to know the new guy as well as you can before you ever start going out.
wow, didn't know they all liked the same person, but the answer would be no, my crush is not over their ex.
amount of time you think of him/her
When your ex doesn't ever talk to you. sometimes your ex might just want to be your friend though
If he has nothing to do with her and you have the trust in him when he says that he is.
you dont
When he goes out with somebody else and he says that it is over between you and him or you and her.
No of course its not bad! But, if you for sure know that it's totally over and you two are not friends don't waste your breath, because it probably will not change.