Interestingly, your beliefs actually come from the way you interpret your experiences.
For example, two people can have the same experience but give it two different meanings. This could occur when two people lose money on the same investment.
One may see this as an example that no one can be trusted, where as the other may see it as a lesson in the risk of investing. This illustrates how one experience can result in two different beliefs.
As your beliefs are reinforced over time, they move into the unconscious mind.
Sometimes you hold these beliefs for life and sometimes they are replaced with new ones as you grow and have new experiences.
The new beliefs may or may not be beneficial or desirable to you.