How many years do you have to live together for a common law marriage?

Where the myth comes from

Probably from old presumption-of-death statutes, which used seven years of absence, and from decades of repetition in popular culture. No state statute has ever made cohabitation alone into a marriage.

What courts actually look for

• A present, mutual agreement to be married — not an engagement, not an intention for the future.
• Living together in a recognising state while that agreement was in force.
• Public conduct consistent with marriage: joint tax returns filed as married, the same surname, spouse listed on insurance, health-care or pension forms, references to «my husband» or «my wife» to family, employers and neighbours.

Length of the relationship is evidence of the agreement, not a substitute for it. Twenty years of cohabitation without holding out has repeatedly been held not to create a marriage; a shorter relationship with consistent documentation has.

What cohabitation alone gives you

Very little by default. No automatic property rights, no spousal inheritance, no right to make medical decisions, no spousal support on separation. Couples who want those protections without marrying generally use a cohabitation agreement, joint ownership documents, a will, a health-care proxy and a durable power of attorney.

Why this comes up

Usually at the worst moment — when a partner dies without a will, or when a long relationship ends and one person expected marital rights that never existed.