Are you desperate for avocados but unsure of how to pick one out at the grocery store? What you want is a good, oblong avocado because of the pit, reports LifeHacker. In three different comparisons of avocados with identical weights but different shapes... ...the longer, pear-shaped avocados had smaller seeds than the more-rounded ones. Since you need two to four avocados to make guacamole, get the most for you money. The caveat is that seed size cannot be guaranteed in every case: You still might choose the perfect oval and get rewarded with an absurdly large pit inside.