If you do someone a favour would you expect them to do you a favour at some point in time?

I can expect until the cows come home, and with some folks I'd never hear a single moo. Others will pester me until they return every one of the eight potato chips I gave them.

I do nothing I expect a return for. I do it because there's a need I can help with. If circumstances change and I need help, I don't 'call in favors.' If they can and will, fine. If not, that's okay too.