Requests from data subjects who wish to exercise their right to erasure can be quite infrequent, and that makes it more important that you have a clear and well-rehearsed policy and procedure in place when they do. Often this may form one part of your overall data subject rights policy and procedure.
In some cases you may not be able to erase all the data immediately, perhaps where financial transactions are involved, and other legislation can often affect this. You may also need to address data held in backups.
Why not check that your policies include the latest guidance from the ICO at https://ico.org.uk/for-organisations/uk-gdpr-guidance-and-resources/individual-rights/individual-rights/right-to-erasure/?