This article explains the four essential estate planning instruments for New York and New Jersey residents: wills, trusts, powers of attorney, and health care proxies. It covers intestate succession and its consequences under EPTL Section 4-1.1 and N.J.S.A. 3B:5-3, the probate process in New York Surrogate's Court and New Jersey Surrogate's Court, revocable living trusts and the critical trust funding requirement, beneficiary designations and their interaction with wills and trusts, the risk of naming a trust as retirement account beneficiary, durable powers of attorney under New York General Obligations Law Section 5-1501 and New Jersey law, health care proxies under New York Public Health Law Section 2981 and N.J.S.A. 26:2H-53, living wills, private asset inventories, the importance of periodic plan review, and the most common estate planning failures including unfunded trusts, outdated beneficiary designations, the will-avoids-probate misconception, and reliance on online templates.