Warning notification that states, "The file is not rebuilt...," keeps popping up even though the model or drawing has not been changed since the last save and check-in.  Yet, you check in an assembly, and check it out, multiple files that were just rebuilt, saved and checked in now indicate the same warning.  It allows you to check-in the assembly model, but I can't help but think when there's enough of these warnings, it impacts performance and speed.