All I will add to the very good information in this thread is that:
1. Books, ALL books are typically obsolete by the time they leave the printer and go into distribution.
2. Internet content can be updated quickly, daily if needed.
3. Smart phone apps can similarly be updated, provided this is done by the author regularly, or as is the case with
www.booking.com or
www.gronze.com, the mobile app connects you to their mobile-sized web application.
4. MOST IMPORTANT - Your smart phone and charger, with all the myriad apps and "tools" in it, likely weighs less than the
Brierley or most other guide books. Don't take my word for it. Use a postal or diet scale and weigh you phone with charger and cable. I was surprised. YOU make the choice - paper or electrons...
I did my first three Caminos using a flip phone and a separate iPod Touch requiring Wi-Fi, available at cafes etc. I carried the
Brierley guide as well. In late 2015, I "surrendered" and invested in an iPhone 6s. I am now a smart phone lover for using on the Camino; NOT an addict mind you, I still use discipline in my daily usage. But, I will go so far as to state that if Mr.
Brierley does not soon move his complete guides to the smart phone app world, he is going to start losing adherents.
Working at the Pilgrim Office in Santiago for the past three years, it has been my empirical observation that more and more younger pilgrims are relying primarily their smart phones. Due to the relocation of the office this past year, they could be seen navigating to the new location using their maps functions and apps. As the "Millennial Generation" start to do Camino more, they will likely (IMHO) not tolerate using BOTH a smart phone AND a paper guide book. As useful as it is, any analog guide book carries a weight penalty that more and more pilgrims are less and less willing to tolerate.
Also, for those of you who still favor starting with a paper guide book and tearing out only the pages you need, disposing of the pages you no longer need as you progress, consider that some of us, including me, consider this somewhat of a "sin" against civilization and knowledge. I was raised to treat books, ALL BOOKS (even the ones I viscerally despised), with reverence, as they represented the summary of our knowledge and civilization. Willful destruction of these items amounts to desecration, at least IMHO.
So, to you lot, I implore you to adopt a digital solution. It will provide many more and very useful tools for you on your Camino. It saves weight; one device does so much more than multiple physical devices: camera, GPS, internet access, weather forecasts, locating needed services, text messaging, phone calls, etc. Of course, in a supreme moment of need, no smart phone can provide "field expedient" toilet paper...
But, I digress...
I consider the smart phone to be an electronic "Swiss Army Knife" sort of device for the 21st century. I admit to be a late adopter, but that was my choice. I am glad I made the change when I did.
I hope this helps the dialog.