Hi,I purchased my 3d approx 4yrs ago.and have read my manual many times over trying to get as proficient as possible with my 3d,but doubt seems to creep in on days where I seem to be digging a lot of trash. Since the manual was printed in the early days of the 3d's introduction has there been any changes to the suggestions given in the manual compared to what has been experienced in real life detecting . Should I continue to follow the manual to the "t" ? thanks DJ