I have worked out with a personal trainer and I know quite a few personal trainers as well. A good personal trainer not only provides motivation but is a teacher of proper technique, form and creative exercise. Results can be dramatic when consistently working out with a trainer. Working out with someone who will vary the routine on a consistent basis will also challenge your body in a way that's more difficult to achieve on your own. It's also great to have someone that can answer your questions about exercise and diet. If you can afford it, working out with a trainer, even just two times a week, can be significantly more effective than just doing your own routine.