I have been on many guided hunting and fishing trips and I even guided for a few years when I was a younger man. 10% is fine but as stated remember all who have worked for you. We always make sure to take good care of the camp cook and if you are staying in a lodge the personnel who clean the lodge and make sure you have a clean room and clean sheets to sleep on. The most important part is to make sure you tip according to what you get. I saw one reply where a guy said he tips ten percent no mater what because he feels obligated. That is not the right way to do it. If you tip a guy 10% that didn't do his job then he will give the next guy that he guides the same crap service, why work harder if your going to get paid anyway. Consequently if a guide goes out of his way to make sure you have a great time whether successful or not, tip accordingly. Remember its a hunt not a kill. A good guide will definitely make or break a hunt no matter how much you pay for the service.