It's always a shame to lose expensive items but quite possibly you value your data, such as photos and email, more than the box of tricks that lets you access it.
Let's work on the assumption that you have allowed Google to backup your photos and so on, and that your email and other files are also 'in the cloud'.
Imagine, then, that you've lost your phone or tablet. You have a few choices. You can:
1. Do nothing
2. Locate the device
3. Lock the device
4. Wipe the device
Options two, three and four usually involve installing some third-party security software.
Arguably this is one of the best reasons to install an anti-malware product into an Android device because there's little chance of accidentally becoming infected if you stick to the Google Play store. According to mobile security firm Lookout those in the US and Western Europe were very unlikely to encounter malware on their phones and tablets.
That said, last year Google enabled the Android Device Manager (ADM), which is included in recent versions of Android. This does the job nicely without the need for third-party software.
Visit the ADM webpage and log in using one of the accounts associated with one of your devices. You will then see a list of all compatible Android devices that you own.
If you have simply lost your phone then the location feature could help you track it down. You may wish to use the lock feature before you start looking, just to be on the safe side.
Locking the device also allows you to pop up a message for anyone who finds your device, so you could provide details for its return (with or without a reward).
Ultimately, though, if you think the device is gone for good you might as well wipe it. If someone finds it they get a fresh second-hand device but your data, login details for your internet accounts and so on are no longer available.
The video below shows a very quick (around two minutes) summary of what you can expect to see (and what the thief sees) when you first lock the device, providing a message to help them return it.
We'll also pretend that we've given up on the idea of ever seeing our tablet again and wipe it completely.
The tablet above is a Nexus 7 that was encrypted for extra security. None of the above techniques will work if the device is offline, which includes being turned off. That means encrypted devices, once rebooted, cannot be wiped as they will never get to the point of connecting to the internet - unless the thief knows and uses your encryption password.
The upshot of this is, if you encrypt your devices and then lose them you should issue the wipe command as soon as possible. If not, when they inevitably run out of power, you'll have no way to contact them. Of course, with encryption in place you may not care.