Everyone needs an estate plan, because part of planning is ensuring you have named agents to speak for you in case you are injured or not able to speak for yourself. The size of your estate, is not a factor in deciding whether you need a plan.
Estate planning includes lifetime planning and death planning. Estate planning provides the "who, how, when, where, and why" when you are incapable of making your own decisions and when you die.
Most people think if they end up in the hospital that their mom or dad, or husband or wife will be able to make medical decisions for them. Not true. You need to sign a power of attorney in order to give someone else the authority to speak for you if you are incapacitated.