I got a Masters in Software Development, part time evenings, studied over 3 years. I don't think it's strictly necessary, but in my experience, it doesn't harm your prospects. I think it's nice to have the combination of experience and education, personally. Certainly don't underestimate the commitment if you study in your spare time. Also, you may enjoy the course, work on new things, meet new people - all can be valuable in their own right.