An issue that seems to be here to stay for the foreseeable future is the atrociously poor battery life of modern smartphones and hence, the plethora of solutions that we come up with to mitigate the situation. This ZDNet article has various suggestions, from the sensible to the sublimely ridiculous.
It is definitely worth taming connectivity features such as bluetooth (you may not have thought of AirDrop) and reducing unnecessary background services (you may not have explored the screen allowing you to tune which apps are allowed to perform background downloads).
On the other hand, blocking your telephone's ability to receive phone calls in order to preserve battery life reminds me of the Fawlty Towers sketch in which the deaf Mrs Richards keeps her hearing aid turned off for the same reason...
If you find yourself tinkering too much with settings in an effort to scrape a few extra per cent out of your battery life, it's probably time to treat your iPhone to a secondary portable battery, and if you're on the road all day, making sure you plan your coffee breaks around cafés that have charging stations :)