I've traveled for many years and I've never found tipping front desk clerks necessary for an upgrade. I've also worked in the airline industry and it can get old, fast, doing repeative tasks. I try to call ahead, confirm or sign up with thier travel club (I agree, that's essential. Sometimes there's extra 'brownie' points for clerks to sign up more members) or give them my number and chit chat - a joke, ask them about themselves, a recommendation, what's going on in town, anything to break the monotony, and eventually ... "how busy is the hotel then?" then the upgrade question. They've always answered very frankly about what's available and what they can do or what I need to do to get one. I'm pretty sure front desk clerks have a "stand by list", behind the desk for people showing an interest in upgrades - at least it's noted such that I usually get a comment about if it was available or not. 100% if I haven't gotten one, the hotel has been busy. People are people. Once in awhile I'd get a 'hollywood' type checking-in when I worked at the airline, who'd want a whole row and everyone around them displaced. Huh? No, I don't think so. But someone else, who makes a nice statement, a joke, showed patience, humor or makes the day better in any way, and they'd get whatever was possible - if it was possible. The point is that I doubt anyone in the customer service field would risk facing an angry customer (or an even angrier manager) and bump them out of something for just a $20 tip. Everything front desk clerks do have their personal sign on it. I've always tipped maids at the end of my stay. I never thought about tipping maids daily and I will have to look into it on my next trip. I just assumed they pooled tips like many resturants do. I always ask for extra coffee, towels, pillows, etc. I've checked with van drivers and very few were paid by the hotel. Most work for tips only and considering the taxi fare they save me - I'll tip either a $1 each way for short frequent trips or half the price of a cab if it's long or a special trip. I rarely have more than carry on luggage or I'd tip them if they helped me handle that. Most my trips are by plane, so I haven't used valet services and don't need concierge services. Generally, I figure any special request that puts someone out of thier way deserves an acknowledgment of some sort. Writting a complimentary note to the head office, eventually will find it's way back to the local establishment and put a feather in the cap for some manager and thier employee. That can be as good or better than a tip in some cases. It's a moral booster and good service is worth noting as much as poor service is. This is interesting to hear how other people view tipping and service.