I would say “10”!!
And in past,before I started practicing mnemonic techniques,my visualization used to irritate and frustrate me! Anything that I heard,read,even touched,my mind’s eye would automatically convert it into images! This would make things ‘vague and complex’ for me to understand,as I would have difficulty to manage and process multiple inputs…kinaesthetic,imagery,auditory,etc! I didn’t realize back then that imagery is my brain’s dominant and natural way to understand the external world!!
Nobody told me back then that I needed to capture ‘images’ in my mind by using things like Mind Palaces or Peg list! The problem with imagery/visualization for me is,images,though very vivid,are very fleeting and fast. I needed a way to capture those images(important ones!),so I could process them slowly. And MP solved this issue of fleeting and fast images for me!
However,not everyone is highly visual. And it is OK…You don’t actually need to be highly visual to use mnemonic techniques. Some people have “Aphantasia”. Still,they are able to use ‘mnemonic’ techniques. They use ‘concepts’ instead of visual images in their mind!