Martin Lewis warns that inheritance tax isn't just for older people and urges proper estate planning to avoid hefty tax bills. With the number of estates paying inheritance tax expected to rise, Lewis highlights that anything left to a legal spouse or civil partner is tax-exempt, but this doesn't apply to common-law partners. Estates under £325,000 are tax-free, but you can protect up to £1 million with careful planning, including writing a will. He emphasizes the importance of having a will to ensure your wishes are honored and to avoid costly intestacy rules.