this means how many coins total have you sent to grading services in your entire life so far. this includes PCGS, NGC, ANACS, ICG and any other grading services.
As a collector of mainly Canadian Victoria Large Cents and Varieties, I have approx 9,000 and have never sent a single coin to a TPG. In my specialty, I feel that I know more about what I'm looking at than someone else with an unknown opinion(and knowledge) who writes it on a label. In my estimation, the money that is wasted on TPG's can buy a lot of coins.
When i see countless coins graded then cracked out and re graded and getting a better grade than the first shows me its a waste of time and more of ones opinion than a meanful grade. When i look at a coin in a slabe all it says to me is on that given day the people that graded it chose that grade. Do you think it might have gotton a worse or better grade if it had been graded the day before or the day after? A total waste of ones money i think. No two people see a coin alike.
Whenever I plan to trade or sell a coin, I send it off to be graded. I personally don't care about having my coins my coins in slabs, but when I buy a high price coin, it is nice to know that it is authentic.