I do not think about efficiency. It is very easy to read the watch, and easier for sure compared to the perpetual calendars which I have (which are also smaller, and less legible). I like that the Sky-Dweller is easy to set too, so after some days or weeks or months of no use, it takes just a little bit of time to set the time and dates and go. Very different from my pc where I will need to clear space on my desk and find a zen time to get it done right.