Let’s keep it simple. The most deleterious and shockingly common estate planning mistake is a lack thereof. Seemingly obvious, but nonetheless a dire mistake. Probate is a harsh, costly, and time-consuming process, and happens to come at a time when no one wants to deal with it—immediately after the death of a loved one. Estate taxes that could have been avoided are also a sad burden for the estate to carry, where the oftentimes court-appointed family member that acts as personal representative for the estate has to watch a large chunk of his or her inheritance go to the government.