As a wheelchair pusher at ORD for the past two years I know exactly how my fellow co-workers and I feel about tipping. It is mandatory. Yes, it is a customary service but we get paid very little and by that I mean below min. wage. The only difference between us and a waiter is that a waiter can ask for a tip, if we do it is against the law. Now I cannot speak for the whole airport but I work at the international terminal and we do alot for the people in our wheelchair. We get sent to a flight and wait there for a good 30 mins and then we pick up our passanger and have to wait in passport control which can take up to a hour. After that we are required to handle all of the baggage go through customs and take the person to their connection flight. Which we have to take them through security and to their gate. In all a connection takes anywhere from a hour to three.Than we have to go all the way back to our terminal and wait for our next chair. We are lucky if they just stay in chicago. But after all we do for people we still either get a thank you or sometimes three dollars.Yes it does feel good to help out people but after doing all you can to make things easier for someone you would expect a little more. So as for a honest tipping guide I would say $5-10 for a non-connection flight with two or less bags. $15 for three or more bags and no less than $20 for a connection flight. I'm sorry if I come off as rude but it gets a little bothersome when you are trying to save up for school and the tips are just not cutting it. So next time when you get assitance think about all that person has done for you and tip accordingly.