I will add just a little bit more... As everyone stated let what you hear dictate how you call! Also if the tom seems to hang up or is answering you but just won't commit to come in and if moving is not an option( like if you don't know exactly were he is and don't want to get busted) try not calling for quite a few minutes. 10 to 15 is a good number. Give him the illusion that the hen isn't interested anymore or that a tom has invaded his space. If he is the dominant tom, he won't stand for that and it may cause him to come in to investigate. Or you may try to vary the volume of your calls. If you are using a diaphram call, try cupping your mouth to lower the volume... so that it appears you are moving away.
As far as your question about moving, I think it depends on what type and size of land you are hunting! If you are on private land, you probably have more options. As far as time goes, thats also up to you and what you want out of your trip! And it also depends on how much time you have? If you have all day, take all day and just enjoy it! JUST REMEMBER, the next spot isn't always the best spot!!! Good Luck and Safe Hunting!!!