Protecting your privacy

A second number is the single most useful thing you can do, and it takes ten minutes. Keep it for this and nothing else, and do not link it to your main email or your real name.

Use a separate email address too. Free, no personal details in the address itself, and not one you have used anywhere that carries your name.

Photos taken on a phone often store the exact location where they were taken, along with the date and the device. Sending an original file can hand over your home address without a word of text.

Sending through WhatsApp, Signal or Telegram usually strips this, because they compress the image. Sending by email or as a file attachment usually does not. If you are unsure, screenshot the photo and send the screenshot instead. A screenshot carries none of the original data.

Card and bank payments appear on a statement with a name attached, and that statement may be read by someone other than you. Think about whose name is on the account before you use it.

Cash leaves no record. If you use anything else, understand that a record exists somewhere and consider who has access to it.

A phone number is often enough to find someone's profile, because many apps let people look up contacts by number. This is why the second number matters so much.

Check your own settings while you are thinking about it. Both WhatsApp and Telegram let you hide your profile photo and your last seen from people who are not in your contacts, and Telegram lets you hide your number entirely.

Delete the conversation from both the app and its backup, because deleting the chat does not always remove it from a cloud backup that runs overnight.

If you used a second number and you are finished with it, retire it rather than reusing it for something ordinary.