Chase unexecuted warranties while the leverage still exists

Collateral warranties owed at the start of a job have a way of never getting signed, because everyone is busy and nothing seems to turn on them until it does. Chase them while you still hold something the other side wants, a payment, a retention release, a final certificate. Once the account is settled a warranty you were promised becomes a favour, so chase early, chase in writing, and record each one as it lands.