I am never sure about the tip jars. I usually give them something if they are pleasant. I do not know what is expected though. Are they like waiters and waitresses who are paid low wages and are expected to make money on tips? For me, that is main reason to give tips. Thus, I always give them 20% plus to servers regardless of the quality of service. Frankly, it's often easier to order standing up rather than waiting for a waiter to to take my order and then waiting again at the end of my meal to get a bill. I appreciate the work that they do, but they aren't really performing a necessary service for me and I only pay them because they need the money. I don't eat out that much and when I do it's often because I'm in a hurry after a long day of work and I don't feel like preparing a meal. I'd rather tip the cook and dish washer.