Haggling--when to do it

Hello!
My husband and I recently moved to Tel Aviv. Before we arrived, we were told by countless Israelis that we would have to learn how to haggle at shops. But this doesn't seem to be the case so far--we can't really figure out at what places were are supposed to be haggling. For example, do you haggle a fruit market where the food is weighed and you pay the price listed according to weight? Do you haggle at any kind of market, or just markets for used things?

Any advice would be appreciated!

I've been told the same thing, so I'm going to be watching this question carefully, hopefully someone will have some great answers! We seem to have a lot of the same concerns and issues. How are you liking it so far?