Rule #15: Consistency is good.

But how do you make decisions when it’s complicated?  Let’s compare some of the situations.

A vs. B: No-brainer.  Of course, go for something better for the situation assuming all choices are inconsistent.

A vs C: Again, no-brainer.  Of two equal solutions, choose the one that is more consistent with the rest of the experience.

A vs D: Consistency here is strong in D, but A is a much better solution for the situation. D feels like shoehorning the UI into a situation it wasn’t designed for.  In these cases, you should create a new pattern for A and make it part of the accepted standards.

A vs E: This is the hardest one to swallow.  You should accept E.  Consistency trumps perfect for the situation.  Always resist creating new patterns if you can help it.  New patterns make learning your app harder.  Don’t jump to this conclusion.  Go with E because it is more consistent.  Only create a new pattern if the new pattern adds significantly to the overall experience.

It’s hard to make these choices in real-time.  I hope this little chart helps you out.