We did a poll on another forum recently and very few people seem to check the chart updates regularly and we couldn't find anyone who actually drew anything on their charts!
'course I always does
It would certainly be a great help if the information was presented in a more user friendly way (cf grid references) I could even suggest that important changes be accompanied by little self-adhesive stickers to stick over the altered section on your chart - perhaps one of the chart suppliers would think this is a good idea for a subscription service?