How do i know where i have to use reflection in C#? [on hold]

Is it usefull to use reflection is c#? Or it just has some information about which class or namespace include this method or properties something like

System.Type type = typeof(int),

also know i can invoke some method but i cant understand how. So could you help me to achieve benefit of reflection. So, how do i know where have to use reflection in C#? I am so sorry if my English is bad.