This is good for usability, but it's not great for security. If you turn off two-factor authentication for a trusted device, you can make it easier for hackers to access your accounts, so you should be aware there is a trade-off.
There's also the fact that if you lose your phone or computer, you can't be certain that the thief won't find some way to unlock it.
Fortunately, most websites give users the option to remove any of their previously trusted devices in case they are lost or compromised, so keep that in mind.
Do I risk locking myself out?
In most cases, your phone will be central to your two-factor authentication experience. It will be used either to receive codes by SMS or to generate them using special apps like Google Authenticator. But phones are easily lost, stolen or broken.
The good news is that most online services have contingency plans for those scenarios. Some companies allow users to specify a backup phone number that can be used for account recovery. Others provide backup codes when turning on two-factor authentication that can be printed on paper and kept in a safe place.
If these options fail, you will most likely have to call or email the company's technical support department and prove the account is yours, for example by providing information about the account that only you would know. Either way, getting completely locked out of an account is extremely rare.
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