in delay design decisions, we talked about not refactoring ahead of time when you don't know what problems lie ahead. that was all true, but that only applies to projects in their initial stage. this doesn't apply to multi people projects which are past that initial stage.
so if you are working on multiple projects, then note that they may require totally different approach to things as basic as refactoring. the rules which apply to one might not apply to other. usually asking the question "can this be improved" takes you to a crossroad where you have all the options cached into your head to decide what's best.