If you have a relatively small estate with no real property (i.e. a home, condo etc) you should...at the very minimum...have a Will, Advance Health Care Directive and a Durable Power of Attorney for financial purposes.
The Durable Power of Attorney typically becomes effective if you become incapacitated (i.e. incapable of handling your affairs). It allows your attorney-in-fact to deal with your assets in a fiduciary capacity for your benefit. Your bills could be paid and the attorney-in-fact could interact with the IRS, Social Security Administration and other government entities on your behalf.
DF