Sketch Status is a simple but powerful addin that gives you more control over your sketches.
Open a part or sheet metal part and all the sketches in the file are automatically renamed to show their constraint status.
In the example above Sketch1 is fully constrained, and Sketch2 is under-constrained.
If you know the importance of fully constraining all your sketches, you know how important this addin is.
It's free, so there's no reason you shouldn't try it.