The senior title comes with many responsibilities that exceed the previous stages. For example I'd expect a senior to be able to take a well rounded approach to

The senior title comes with many responsibilities that exceed the previous stages. For example I'd expect a senior to be able to take a well rounded approach to problem solving. They need to be able to use their years of experience to bring in technical value to the company. I guess the rest depends on the actual job spec. Normally you'd find the list of responsibilities to be longer.