Every week it seems I read about someone who lost their camera, bungled an OS upgrade on their tablet, or had a phone stolen, and they are lamenting “There’s three years of irreplaceable family photos on it, of great sentimental value and they are all gone!” (cue the tears and gnashing of teeth).
Seriously? What are your photos doing still on your camera flash card or your phone?
Flash memory cards are designed to hold your photos just long enough to copy them to your computer. They are not designed for long term storage. Aside from theft or loss by dropping into the (ocean/Grand Canyon/thrift store donation box/porta-potty/take your pick), flash memory cards have a finite lifespan, and when they fail, they don’t usually give any warning at all.
So here is the drill.
Take your photos, and then at the first opportunity, copy them into a computer. Your own computer preferably, but if you are on the road and all you have access to is a cybercafe or a friend’s machine, then create a Dropbox, Flickr, OneDrive, Apple iCloud or other online storage account and upload your photos to that over a net connection.
Then, because computers can fail too, burn a DVD of the photo data files, label and date the DVD (!) and store it on the shelf. You have room for about 1500 photos on each DVD-r blank disc (give or take, depending on the resolution and file format), so you can organize your photos by date and event.
You can either connect your camera / phone to the computer to transfer files via USB cable, or you can eject the flash card from the camera and use a flash card reader on the computer to read the data. If you don’t have a card reader slot built into your machine, then USB flash card readers are cheap and cheerful. The advantage of a card reader is that you don’t have to turn the camera on (and use up battery power) to transfer, and the reader is generally faster than a USB tethered camera to transfer the files.
If all you have is an iPad or tablet, you can generally get flash card readers for them. Although the memory space of a tablet isn’t sufficient to store a lot of photos, you can at least use the tablet to upload to online storage when you are attached to WiFi (make sure you are not uploading with you cellular data plan, because you might get a painful bill for data overage at the end of the month).
For extended field trips, either plan to take a laptop or netbook machine with you, (which can also access external hard drive storage for extra backup), or you can look into a specialized data backup battery powered portable drive such as the Digital Foci PST-251 Photo Safe II which gives you 320 GB or 500 GB of battery powered backup, with a built in CF and SD card reader (computer not required).
The Kingston WiFi MobileLite reader can hook up to your phone or tablet by WiFi and allows you to back up files to a SD card or a USB keychain drive using the Kingston app. 
There are a couple of brands of SD memory cards that have WiFi built in, so they can automatically copy their contents to your computer if it is within network range.
While we are on the subject of backup, don’t attempt any major upgrades to the operating system of your phone or tablet until you have had the chance to back it up completely. If you have an iPhone or iPad, use iTunes to make a backup first. Otherwise use the software that came with your device. Then, make sure the phone is fully charged or better yet, plugged in. Only then, hit the OK button to do the upgrade to the latest and greatest system.