Breakups are the worst experiences anyone would go through for sure. They can make someone loose their mind. I believe it all depends on an individual, there are those people who can bounce right back and continue with their lives as if nothing ever happened, and there are those people who would even fall into depression after a break up because they cannot live with the thought of not having their spouse with them. There are many reasons why people break up, it could be because of rivalry, finances, misunderstandings, infidelity or insecurity and many other things. People are different, so depending on what it is that caused the breakup, that is what will determine whether someone will move on immediately or will take longer to get into another relationship. But i think the best time to start a new relationship is when you know you are completely over your ex, with this i mean, you don't get bothered about anything they do.