Certified ServiceNow Application Developer and Implementation Specialist Rob Pickering, has another tip for us. The advice Rob wishes he'd had as a ServiceNow developer just starting out, was to follow best-practices more closely. For example, Rob says:
If you wish to modify an out-of-box Business Rule, then copy it, set the original to inactive, and then make your modifications to the copy. This will preserve the original business rule and it will upgrade properly, giving you an opportunity to evaluate if your changes should be deprecated in a new release.