We tip our housekeeper about $20 + lunch every time. Our gardeners get $10/each and a beer every time they come, unless they piss me off by doing something stupid. In that case, they just get a beer and more explicit instructions. All of our takeout and delivery guys are tipped at least 15% per order. We have a weekday cook whom we tip in transportation and food. The motivation is similar to what was mentioned above: we make a lot more than they do, and we definitely remember what it was like to bust your ass for a lot less money. We know how much a tip meant to us, so we are going to make certain we pay that forward.