There’s a broad spectrum of SD cards available, all of which have wildly different performance levels. If you use a low-quality card, you’ll quickly become frustrated with all the delays.

This is especially true if you move lots of apps onto the SD card. Loading times, refresh rates, and sync speeds could all decrease dramatically. Sadly, most people likely suffer from this. They use any old SD card they have lying around without considering whether it’s the best tool for the job.

If you only plan on storing photos and files on your SD card, either of the two fastest card types—UHS-I and Class 10—will be sufficient.

However, if you plan on installing entire apps on your card, you also need to look out for the card’s app performance class. A1 and A2 are the two options available; A1 is faster.

2. Vanishing Shortcuts and Forgotten Passwords
During my recent usage of an SD card in my Android phone, I ran into a curious issue. Every time the battery died (which, due to its age, was frequently), any shortcuts for apps I had moved onto the SD card vanished from my phone’s home screen.

As I like to keep my home screen organized into folders, it was seriously annoying.

And worse still, some of the affected apps—including Twitter, MyFitnessPal, and Reddit—also lost all their saved passwords, settings, and other user data.

I’m not going to pretend to know why this happened, nor can I promise it will happen to you. It is, however, indicative of the types of unexpected issues that can arise when you use an SD card with Android.

3. Finding Files Is a Nightmare
Although you can format your SD card so it becomes adopted internal storage, that doesn’t mean that your phone will see both disks as a single entity. Therefore, depending on your usage patterns, it might become cumbersome to find the files you need at a given time.

For example, you could end up in a situation where different types of data are stored across the disks. You might have photos and local music on your SD card, but your offline Google Docs and downloaded Chrome files in internal memory. The more apps you use, the more problematic this fragmentation will become.

Are you confident you can recall which apps save their files on which storage unit, months after the initial setup?

It could all hinder your productivity. It might leave you with duplicates taking up unnecessary space, and result in a breakdown of your file management systems.

4. SD Card Failure
SD cards have a limited number of read/write cycles. Every time you access data on it, the remaining lifespan decreases. Naturally, the lifespan also varies depending on the quality of the SD card. A SanDisk product will live longer than a cheap no-name card from eBay.

How to Pick & Buy the Best SD Card for Your Needs How to Pick & Buy the Best SD Card for Your Needs What kind of SD card is right for you? Not all of them are the same, after all. Here are the minimum specs you should aim for depending any given activity or need. Read More
To further complicate the problem, you might not know how old a spare card is. If you use an old SD that sat around gathering dust for years, you probably have no idea how much use it got in the past. You’ll thus not know how long it might keep plodding along.

And remember, unlike traditional hard drives, there might not be any warning signs before an SD card fails. If you don’t have backups, you could lose lots of vital work in seconds.

5. Migrating to a New Phone Is Frustrating
Perhaps contrary to many people’s understanding, an SD card on Android is not necessarily analogous to an SD card (or USB flash drive) on a PC. On a desktop or laptop computer, you can move your card or flash drive between different devices and access your files without problem—they are portable.

If you try to move your Android phone’s SD card into another phone, or attempt to access its contents on a computer, you will probably be out of luck. Why? Because when you set up an SD card as local Android storage, the card becomes encrypted to its host device.

Thus, if you buy a new phone, you cannot simply move your card and carry on. You have to format the card’s data (losing everything) and start again from scratch.

6. Reduced Gaming Performance
Some of the most significant storage hogs on Android phones are games. This doesn’t mean simple titles like crossword games, but rather those with high-end graphics and extensive gameplay. The app’s files and your saved games can add up to several gigabytes’ worth of data.

It might be tempting to move such games onto your SD card, but this is a bad idea. Even the best A1 Class 10 SD cards will not perform fast enough for modern Android games.

You’ll end up with gameplay glitches, missing graphics, and frequent crashes. These are the types of drawbacks you don’t think about when you consider the pros of using an SD card with Android. I learned the hard way; don’t waste your time.

Your Next Phone Needs a MicroSD Card Slot -- Here's Why Your Next Phone Needs a MicroSD Card Slot -- Here's Why Some popular phones don't have microSD card slots -- but a lot still do, and you need one! Read More
Still Planning to Use an SD Card?
If you’ve read and understood the points we’ve made, but you still want to press ahead and use an SD card in your Android device, you need to make sure you know how to move apps and data across.

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