When working at height you will be facing a whole range of differing environmental issues that will look very different from the ground. For example, power cables and protruding building features.
If you’re using some sort of basket crane for example you need to ensure you have plenty of head room for not only the crane and you, but also for any equipment you’re taking with you.
Although all cranes have to pass very stringent safety tests and will work at many extremes, it’s important you keep well within the tolerances of the particular piece of equipment. They’re only as safe as the person operating them and if you drive one into electrical cables, you are likely to cause a lot of damage.