Estimating remaining daylight hours.
You need around three hours of daylight left when you set up camp, to minimise the difficulty of setting up in the dark, and to find addtional things you may need. A stunningly simple method of working out hours left is to use your fingers (but not your thumb). Four fingers between the sun and horizon, means one hour left. Three hands, (without thumbs) means three hours left. One finger equates to 15 minutes. Try it this evening, you will never need a watch or smart phone again!
*Actually keep the watch so many other uses, and they are elegant.