W-9 forms do not expire.
Most W-8 forms have a life of 3 years from the end of the year the form is signed. For example, information provided on November 2, 2018 will be valid through December 31, 2021.
You must provide updated tax information whenever a change in your circumstances makes an existing form inaccurate. Please follow this link to report any change of circumstance, including a change of tax address: https://angel.co/invest/tax-documents