You cannot measure the real cost of something without looking at what had to wait.

The cost of a project is usually measured in what it took: money, hours, effort. The larger part is what waited: the relationship that got less attention, the health habit that lapsed, the other work that stalled for a year. Those costs are real, delayed, and almost never entered in the accounts.

When reviewing something you have committed to, ask what has been waiting since it started. Check whether the wait is still acceptable. Some things cannot wait indefinitely without changing.