A log of digging trips would help show your level of experience and interest in the sport nicely. I would however shy away from logging every trip to the same dig, perhaps just put in an estimated number of hours per month or something similar.
It's similar to instructors logging every single trip they do down the same intro cave (e.g. Carlswark) with kids, after a while there is no merit in relogging the same info, just a monthly or yearly summary.
Hope that helps.