I receive a sense of satisfaction from helping others become more efficient and not be frightened of the big new PC sitting on their desks. These are the main reasons I entered the training profession and why I stay. Working part-time does more than give me a psychological boost. It also benefits me professionally. If I did not work at all, my skills as an instructor would degrade.
Trainers have to think on their feet and be ready for a large variety of questions.
By teaching and researching software on a regular basis, I can be ready for just about anything. Many students have similar questions, so knowing an answer from a previous class will help me in the next one. Software is always changing and evolving. Part-time employment helps me keep abreast of changes from one version to the next. Obviously, knowing how to utilize Windows 3.1 is not going to help me teach a Windows 95 class.