For peace of mind, to know that the people whom you love will inherit from you as you would wish.
To avoid expensive, protracted administration at what is a very difficult time for your loved ones.
To avoid arguments and fall outs.
To protect someone, you live with who is not your spouse. Cohabitees have very few rights and can find themselves in a very difficult position if you die suddenly without a Will as your family will inherit your assets not them.
To appoint guardians for your children and arrange funds to be held safely for them.
To protect your assets for your children should your spouse remarry.
To state your funeral wishes.
To provide for your pets (sixth most popular beneficiary in a Will).