Mostly I use 6 e/s for one look and I personally don't think that it is too much. It sounds a lot but if you withdraw the two eyeshadows I use for my highlight there are only 4 for the lid and crease.
I use the 6 for:
- highlight (a matte like Blanc Type)
- highlight under the arch of my brow/browbone (something shiny like Solar White or Dazzlelight)
- inner third of eyelid
- middle of eyelid
- outer third of eyelid + about the half of the crease + lower lashline
- outer v + outer lower lashline
I like to add depth and dimension like MrsMay too and I also use a paintpot, paint or shadestick on top of a primer.
For an easy look 3 eyeshadows can be enough, though. For example one for the highlight and inner lid, one for the middle lid and one for the outer v, crease and lower lashline. But I like to use more because I love to play with eyeshadows.