Hidden Content
THE ACTUAL NUMBER of chat messages sent each day is hard to come by, but with WhatsApp alone accounting for billions of users, you can imagine the sheer volume of ongoing conversations.

Not all of those messages involve anything particularly sensitive or private, but a lot of them do—and you don’t want those chats to be seen by anyone other than the intended recipients.

Good messaging hygiene might involve changing apps or tweaking a setting, but it’s important that you don’t neglect it. These five recommendations can get you started.

Switch to End-to-End Encryption
When instant messenger chats are end-to-end encrypted, they’re essentially turned into impenetrable blocks of data. Only the devices of the person (or people) you’re chatting with have the codes to unlock that data, which ensures no one else can read your messages while they’re in transit.

Not even the developers behind the software you’re using can unlock that data, so if an unscrupulous employee wanted to take a peek at your chats, they wouldn’t be able to. If law enforcement requested copies of the conversations, there wouldn’t be anything useful to hand over to them.

Some instant messengers use end-to-end encryption, but not all of them do. End-to-end encryption is deployed by default for Signal, WhatsApp (for personal chats,) iMessage, and Google Messages (with RCS enabled.) It’s also available as an option on Facebook Messenger and Telegram. If you’re using anything else, check the provider’s policies and consider switching to something more secure.

Turn On Disappearing Messages
We mentioned that Facebook Messenger has the option of end-to-end encryption: To enable it, you need to make a conversation “secret” by tapping the info (“i”) button at the top of a chat in the mobile app, then choosing Go to secret conversation.

Once you’re in that secret conversation, another feature becomes available: Disappearing messages. Tap the info button again and pick Disappearing messages, then choose how long messages should stick around after being read. This way of tidying up after yourself protects you against someone reading through your chats if they gain access to them or physical access to your device.

Facebook Messenger isn’t the only app that offers this functionality: You can also find disappearing messages in WhatsApp, Signal, and Telegram, among others. On iPhones, you can delete older conversations in the Messages app after choosing Messages and Keep Messages from Settings.

Lock Individual Conversations
To avoid an unwelcome visitor gaining access to your phone and all of your chats, one of the best things you can do is lock some or all of those chats behind a passcode or other lock—like the protection on your phone’s lock screen.

WhatsApp makes this simple. You can lock the entire app via the Privacy menu in the app settings, or you can lock individual chats: Open the chat, tap the conversation name at the top of the screen, and then pick Chat lock. The options here will depend on the options on your phone (such as fingerprint lock and face recognition).

Other apps offer the ability to lock all of your chats, including Signal, Facebook Messenger, and Telegram, though for the moment the option to lock individual conversations is exclusive to WhatsApp.

Check Your Contact Options
Most instant messenger and social media apps let you control which other users are allowed to follow you, send friendship requests, communicate with you via direct messages, and so on. Tightening up these settings is another way to limit your exposure to the wider world and maximize the security of your chats.

Take Telegram, for example. Head to Privacy and Security in Settings, and you can control who is allowed to see your online status, your profile photo, the groups and channels you’re in, and more. Other apps have similar options, so make sure you know what they are and what they do.

Also, think about the temporary photo and video posts commonly known as stories if your app supports them (a lot now do). These stories have their own visibility settings and may well be public by default.

Know Where Your Chat Backups Are
You want to keep backups of some conversations, otherwise you risk losing all of those records, and all that history, if something should happen to your smartphone.

But it’s important to know what you’re backing up and where those backups live. Backups are another potential route for anyone trying to access your messages without authorization, so you should keep them as well protected and secure as anything that’s actually on your phone. Some apps back up your conversations locally, and few encrypt them, so make sure to check your favorite app’s settings.

As a final precaution, you also need to think about other devices and locations where you’re logged in—Gmail can lead to Google Chat, for example—as well as places any external backups might be stored and how these are protected (take WhatsApp on Android, which can save chat backups to Google Drive).