If you’ve set a password yourself, you can choose how often you’re required to enter a password from your lock screen, which can be anywhere from 30 seconds to 30 minutes, or each time you unlock your phone. If you have a Microsoft Exchange account through your work, the Exchange administrator will set the options you can choose.

This setting is different from how often your phone goes to sleep, which you can set separately.

To change both options:

Step 1: In the App list, tap Settings > Lock screen.

Step 2: Do one of the following:

– To choose how often you’re required to enter a password from your lock screen, tap Require a password after and choose the time you want.

– To choose how often your phone goes to sleep, tap Screen times out after and choose the time you want.

How can I customize my lock screen

In the App list, go to Settings > Lock screen, where there’s a lot you can do to tweak your lock screen to your liking. Try changing the background to a favorite photo or have a picture of the artist shown when you’re listening to music, or choose any combination of detailed and quick status notifications to show you new messages, missed calls, and social network updates.

Via Windowsphone