Try to understand the purpose of these pencils first. If the purpose is coloring pictures – you won’t need 150 shades, unless you want just to have them. A set of 48 colors would be enough.
If you are beginner in the art industry – try to purchase a set of 50-80 colors, then gradually you’ll see which pencil you require the most. Then you can purchase it.
If the set is for professionals, let’s say for architects, they may require the biggest variety of shades and colors.