Beyond needed updates, is there ever a good reason to stick with a certain version of your software or product, or should you constantly evolve, and why?

Remember, software is a tool that helps you achieve your business objectives, not an entity itself. The purpose of your software is to accomplish these objectives in the most efficient manner possible. So with regards to evolving your software, the decision to do so should be made with your end business needs in mind (both now and in the future). If you’re continually building your business and need to evolve the software, then by all means do so! However, if your current version meets your needs and will continue to do so into the future, then there’s nothing wrong with sticking with what works and focusing your efforts elsewhere.