How important is that middle initial?

If you do not use your middle initial then you run the risk of confusion in your legal documents and clouds in your title. However, if you use your middle initial and then leave it out of future legal documents then you may have a whale of a problem. This is especially important in estate planning documents. For example, you sign your trust John E.L. Smith, but you sign your deed putting the house into trust as John Smith. Your document will likely be rejected. As always, use a lawyer to keep continuity in your document captions.