Update PROGRAMMING.md

Author: countable

developers/PROGRAMMING.md

@@ -45,6 +45,7 @@ This is how we build things.
   - We have [Coding Standards](CODING_STANDARDS.md) based on auto-formatters where possible, which include standards for structuring projects which are based upon what we've learned.
   - We operate based on principles in 12factor.net, see [implementation here](../../devops/DEVOPS/)
   - We are intentional about what dependencies we include in [our stack](../../devops/STACK_CHOICES/)
+  - Refactor incrementally as part of your other work, instead of doing [big rewrites](https://www.joelonsoftware.com/2000/04/06/things-you-should-never-do-part-i/).
 
 ## Developer's Guild Meetings