... if you acquire any pipe because of the reason that it looks cool or special, but not mainly because you want to smoke your tobacco in it;
... if you would avoid smoking any particular pipe of yours just to maintain it in good condition;
... if you have more pipes than the # of tobacco in your cellar;
... if you have more pipes than the # of pipes that you 'need' --- [for a person who smokes only 1 blend or 1 kind of tobacco, the # of pipes he 'need' would be max. # of bowls he smoke per day + 1 given that he practices resting a pipe for the # of day based on the # of bowls he's smoked in it, i.e. 2 pipes if he smokes max. 1 bowl, and 7 pipes if he smokes max. 6 bowls; my calculation is 31 (max. 1 month resting period I heard people practice) x 1-6 (approximate # of genre of tobacco) which gives the person to smoke 31 days straight of only 1 genre];
Oh, it seems I am a 'collector' to a certain degree.