In Ireland, the Succession Act 1965, § 77 outlines the requirements for a valid Last Will and Testament
You must be at least 18 years old or married and of sound mind.
The Will must be written and signed by you, or someone else with your permission.
Two or more witnesses must watch you sign the Will and sign it too.
Your signature should be at the end of your Will.
Any changes made after signing won’t be valid.
You don’t need to tell anyone about your Will for it to be valid.
A Last Will and Testament remains valid until it’s revoked or replaced by a new Will. There is no expiration date for a Will.