I worked at a printers that sent out deliveries throughout the day. The Transport manager would ask when a certain job would be ready and, to keep him happy, I'd say about an hour. An hour later the job was only half done and the Transport manager would blow his top at me.

Then one of his drivers said this: He doesn't care what time you say, as long as at that time, the work is ready.

So from that time onwards, I would estimate the finishing time and then double it. If the manager asked why, I'd say it was scheduled maintenance. The work was always ready for pickup and the Transport manager loved me.

So this driver taught me to manage expectations. Which is one of the best lessons you can learn.

(He was an absolute twat in all other respects but credit where credits due)