It completely depends on each person. Some people will need 4, others 10.
I need a solid 8 to function properly.
One of the most important things I have learned when growing up is that I am me. I'm not my dad, not that guy on TV, not that person who can do x, y or z; or who is comfortable doing that.
I have my own strong points and limitations. Discovering those, and who you are, is probably one of the most important things we need to do as adults. Once you start to discover who you are (a tough and painful process filled with disillusionment) and realize that this applies ONLY to you, you will be able to live much better.
I remember reading the 7 habits of highly effective people where the author says: "Advice is like an old pair of shoes, the experience you have works great for you, but like an old pair of shoes, that only works great for YOU"