I know people say there should be a period of alone time between each relationship rather than diving straight back in but I know a lot of people do or relationships over lap. What are your opinions? How long should you give roughly (obviously I know it alters personally but... )

Personally, I don't think relationships should overlap unless there is an understanding that you can date other people. I think to maintain our self-confidence and esteem it's best to end one relationship before starting another. This is not hard to do - if you meet someone and want to date them, you end your existing relationship and then pursue the new person.

How long you take between kind of depends on your circumstances. If you are still pining for the other person, it's good to take some time to process that and get over it so you don't use the next person as a "rebound" situation. If you are not really hurt by ending the prior relationship and feel you understand why it ended and what you want moving forward, you may not need a break at all.

The important thing is that you learn from your relationships so you don't repeat mistakes - either things you do wrong, or chronically picking the wrong person. Some people chronically pick good people and manage relationships well, so they don't really need breaks so much. Others may have jealousy, cheating or anger issues, or may repeatedly choose the wrong girl or guy. A prime example are women who chronically choose abusive men, or guys who continually pick women who treat them badly.

I also think there is value in knowing that you can be alone and be fine. When you have this confidence, you do not cling to relationships for fear of being alone. You rather choose relationships that add to your life. It can also keep you from being too needy in a relationship when you know you're fine on your own. With this knowledge, I think people are more fun as partners and more independent, so they are less likely to suffocate and drain the life and energy out of their partners.

What the person above said is good.

I think its key to be able to be happy alone without a relationship to make you. You should have an active social life and hobbies / career which take up your time without a relationship taking these away from you.