This article is from the PEZ candy and PEZ dispensers FAQ, by sharpe@dg-rtp.dg.com (Chris Sharpe) with numerous contributions by others.
How many PEZ to collect is completely up to the individual. Trying to
collect all the variations of every dispenser is quite a task. For
example there are 56 US release TMNT!! (4 Turtles x 2 faces each
{smile or grimace} x 7 body colors {yellow, orange, black, purple,
green, red, and teal blue}). For this reason, many collectors only
collect dispensers that vary from the neck up. A different color base
is not generally considered a "variation", but a Smurf with a
different color hat or a Charlie Brown with a different mouth is a
variation. Again, it's up to you how many to collect, but the "from
the neck up" rule is generally accepted.
 
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