To me an "all day smoke" is the tobacco equivalent of a "session beer", meaning that you can have quite a few in a short period without losing the enjoyment. For example, it would be easy enough to drink six basic lager-style beers in a row over an evening, but not many people would want to drink six heavily-hopped IPAs in a row.
For a tobacco example, if I have more than two or three pipefuls of medium to heavy latakia blends throughout one day, then sometimes I get the ole leather tongue and my taste will be off for the next day, and my tongue and mouth will feel dry. However, I can easily smoke five or more bowls of a burly blend like Carter Hall without any problems. To me, that's an all-day smoke. Of course that only comes into play on the weekends since I only smoke one or two bowls a day during the week.
For a tobacco example, if I have more than two or three pipefuls of medium to heavy latakia blends throughout one day, then sometimes I get the ole leather tongue and my taste will be off for the next day, and my tongue and mouth will feel dry. However, I can easily smoke five or more bowls of a burly blend like Carter Hall without any problems. To me, that's an all-day smoke. Of course that only comes into play on the weekends since I only smoke one or two bowls a day during the week.