Keep your smart phone

Unless the end of the world is due to a massive EMP, there is a good chance your smart phone will be useful.

Handy Features

 Camera
Most smart phones have a camera, which is good for capturing useful information, maybe more than you want to write down, or something that only a picture can capture.

 Video Camera
Like the camera, but video allows you to record an event, or perhaps a message.  You might want to use the videos as a log of the events.  Capture a message to loved ones or your thoughts as you go about your struggle to survive.

Notes
Jot down some important notes, keep track of supplies, instructions to find a cache you've hidden perhaps or just a journal of events.

Manuals & Books
Electronic versions of books (stored locally on the phone) could be handy.  The Red Cross has some First-Aid Apps that are just digital versions of the manuals you might already have.  They have one for pets also.  Maybe your favorite book on survival in the wilderness, or a cook book for wild game.  Books are always handy.

Compass
It's probably not as reliable or easy to use as a good old fashioned compass, but it's better than nothing.  You're not going to be able to use your phones navigation apps if the networks are down, and even if you have the maps downloaded locally to the phone, the GPS system will become unreliable after a couple of weeks if no one is keeping it updated.  So depending on the nature of the end of the world, that might be a concern.

Music
Maybe you have some music on your phone.  Music can boost your spirits, and help make a boring situation more enjoyable. 

Alarm
Maybe you want to get a couple of hours of sleep, setting an alarm might be important.  And right with alarms is the time itself.  Maybe you need to know the time (although that might be the last thing you care about) Your smart phone can certainly do that.

Flashlight
It's not the best light source in the world, but if you need it a smart phone can either shed glow from it's screen or the flash (usually an LED) can be pressed into service as a flashlight.  You will probably need an app for this, but you should have one anyway.

These are just a few uses.  There is a good chance if you sit and think about it, you'll come up with some more on your own.

Power Saving

If you are using your smart phone, it's probably a good idea to take some steps to save power.  Many smart phones have assorted power saving settings you can access to maximize battery life.  Using those will extend the life span of your battery.  Another thing might be to put the phone in Airplane mode, which is to switch off all of it's transceivers.  Some smart phones have a dedicated setting just for this, others you might have to turn those functions off individually.

Turning the brightness of the screen down can save power as well, or setting it to adjust depending on the ambient light if your phone supports that.

Turn off some reminders.  No sense in letting your phone remind you of your coffee date with friends if it's the end of the world.  Unless these are new friends and coffee date is your code for scavenging run.  Anything you can do to conserve power will help.

Recharging

If the world comes to an end, the way you recharge your phone might need to change.  You might be someone who already lives on solar and battery power, so this isn't new to you.  For the majority of us though, we get the power for charging our phones out of the wall of our house.  And that might not be an option.

Solar Panels & Batteries

Portable solar panels are pretty common, and they can be pressed into service to charge a phone.  What I find works better is using the solar panel to charge a battery that you then use to charge the phone.  It makes it so that you can use the phone during the day (when you will likely need to) and charge a battery with your solar so that you can charge the phone at night using the battery.

Manual Chargers

There are a few hand crank chargers on the market, and assorted devices that turn physical labor into electricity you can use to charge devices.  My experience with these has been varied, but I don't find many of them to be super effective.  It might just be the models I've used, your mileage may vary.

Plan Ahead

This is all about planning ahead and being prepared.  Make sure to examine your options for Apps, chargers, external battery packs, and all of that now while you have the electricity and infrastructure to do it.  That way, if the world comes to an end, you'll have the tools you need to continue using your smart phone as an effective tool.

Until next time, keep prepping!