Agree. I've been at my place for 11 years now, and have had four very distinct roles over that time. Each change gave that revitalizing jolt of fresh challenges, technologies, etc, but with the benefit that I got to keep my seniority, influence, expertise with the in-house systems, and so on.

Have I given up potential pay bumps by not going external? Sure, probably. But I have enough to be comfortable and my company has treated me well, both monetarily and in facilitating these kinds of changes when I've wanted them.