Our sons learnt to use PECS (picture exchange) by asking for food. It was the biggest motivator for them and by about age 4 they were using photos very well to ask for snacks. When your child does not talk, this new found communication is wonderful. You feel compelled to respond to every request because they are actually communicating with you.......the trouble is that 4 years later, when you are still having breadstick photos put in your hand every five minutes by a child who really does not need anything else to eat, you realise that something will have to change!
This is the point we've reached. I think we were able to make some changes because we felt confident that the skill of using the PECS photos was very much ingrained in both boys. If there were any doubts we couldn't have messed with it because of the risk of losing the communication.
This is what we've done.
Both boys have their own morning and afternoon 'snack boxes'. They have a variety of snacks in them that they would ask for anyway so they can still use the PECS photos but when the snacks are gone they are gone! Each box has a named photo so can also be used for name/picture recognition.
It's working very well! They accept that they can't have anymore because, visually, they can see that there is nothing left and they are doing brilliantly at getting the right box from the kitchen. Long may it last!