Favors are designed to be used sometime after the pledge is sworn, but the standard pledge rules make this difficult. By implying that the favor must be used before the end of the pledge, it makes the task difficult to throw in unless someone has an immediate need.
For example, a pledge to deliver a package in exchange for a favor is tricky: the delivery takes one day, but to have time to use the favor, the pledge must be extended to at least a week, if not a month or a season.
To make favors more useful as pledge tasks, favors gain a new Timeframe component. It is defined when the pledge is sworn and can last beyond the end of the pledge. If left unspecified, the default timeframe for a favor is the same as the duration of the pledge.
Refusing to call in a favor before it expires carries no penalty.
Refusing to honor a favor during its timeframe, immediately invokes the pledge's original Sanctions for a period of time equal to the pledge's duration. The pledge is now considered broken by the one who did not honor their favor. This happens even if the pledge's duration has already run out.
All other tasks and pledge rules work as normal, including conditions for breaking the pledge. Once the pledge is broken, no tasks need be honored and favors are no longer enforced, regardless of their timeframe.