For quickservice restaraunts (ie, fast food,) there is generally no expectation of tip, regardless of the delivery method. However, at a place like Sonic (alas, I don’t go there anymore) if the service is friendly and efficient and delivered with a smile, I might feel the urge to toss a few bucks their way, (Two dollars is reasonable.) My thinking is that I can barely tolerate the dopey kids that have no smile, and no ability to communicate beyond a few grunts of “here is your food.” The ones that show effort get rewarded.
Anywhere you sit down, and the server comes to you, the tip is generally about 15% of the tab, excluding bad service. I do not reward bad service, such as a waitress or waiter that tells you how bad their day is going and how their baby’s daddy ain’t paying child support.
Delivery of any sort, its a good idea to tip, assuming the service was reasonable. I had a furniture delivery crew come in once, and I was prepared to give them a tip. The head guy immediately started complaining about how he had to go out of his way and mess up his schedule to come deliver my product… Therefore, no tip. I do not tip if the minion is attempting to manipulate me into a tip… I don’t care about how your day went, I care about whether the service was quick, efficient, and made me and my needs the center of attention.
Valets always get a tip. Always. Bad service or no. Its just good practice, especially if you go to the same places over and over.
People that help me with my luggage always get a tip.
If I am carrying a heavy load from a store, like a television, and a guy helps me out, I will generally tip.
But the rule is, really, if you feel the service was good enough to warrant a tip, go for it, it never hurts.