This is maybe one of the greatest advantages I have gained in my years of experience at one company. When I started, I was inheriting the code of other people, with all the baggage of trying to understand it and keep the mental model intact when I needed to make changes. Over time, I've largely rewritten all of the products that are still current, as requirements and dependencies have changed. I'm reminded of the probably apocryphal story of Nikola Tesla and Henry Ford[1]

[1] http://www.snopes.com/business/genius/where.asp