The Cell tower inspections depend on the type of towers you are flying. I have only experienced 4 different types. There are a lot more out there, I just have not been tasked with them yet. Monopoles, Self Supporting Towers, Guide Wire Towers, and Power Line Structure Towers, are what I have experience on. The Monopoles Towers are the easiest to inspect. Depending on the surrounding obstacles, (trees, power lines, other towers, buildings, etc...) you can completely inspect a tower in about 1 hour if you really work fast. The Guide wire tower can take much longer, depending on the shoot list. I have done 7 monopole Towers in one day. But I must stress the slower the better quality you will come out with. The weather and sun location can also effect your total time.