My cat knows the sound of a cheese puffs so well. You can rattle with any bag of crisps and she won't even lift her head. Accidentally nudge a bag of cheese puffs, and she'll be there like lightning. I hardly ever buy cheese puffs, but she'll still remember the sound after months.

When she was a kitten I'd share a bag with her once in a while. A handfull for me, and a single one for her was the general scale of distribution.