When a one second saving was worth £10K each day

While looking for a new job, I've been thinking about how I quantify the work I've done previously. It reminds me of the time we worked out how a small performance improvement was worth approximately ten thousand pounds (Sterling/GBP) to the company on each day of operation. Six days a week times 52 weeks a year, that's over £3 million per year!

I was working for a courier/delivery company and was responsible (among other things) for the software used to scan parcels in the depots and by drivers when making deliveries. First thing in the morning was a very busy time, and lots of parcels needed to be scanned and loaded onto many vehicles, which often required delivery far-away or on tight deadlines. Time was definitely an essential factor. Saving time taken during this process would:

• Allow more time for time-sensitive deliveries
• Reduce the number of late deliveries
• Allow for increased capacity
• Reduce stress among people loading vehicles and drivers with tight deadlines

We (obviously) wanted to save any time we could.
Through a combination of changes to multiple pieces of software involved in the process (preparing the list of deliveries for each route, the scanning software, and the software used by controllers to organise and dispatch routes/drivers), it resulted in time savings equivalent to one second per parcel. 

One second per parcel might not sound like a lot, but there were a lot of deliveries being made each day. In addition to potentially saving time, that one second per parcel was, on average, enough to enable the addition of one extra delivery to each route each day.
Based on the number of routes and the average price of a delivery, that amounted to approximately ten thousand pounds. Per day. Definitely a successful project.

The monetary value is a notable figure, but no, I didn't see any of that or even get a bonus. My reward was knowing I'd done my job well and improved things for the people using the software I was responsible for.
I enjoyed the satisfaction of solving a complex technical problem (how to make the process take less time) that also contributed to a positive benefit for the people using the software.
More than simply being able to put a financial figure on the result of a change, I was able to use my broader knowledge of the company and its processes and also learn more about it during the project.