UPDATE: A lot of newer phone models from popular vendors have started to aggressively optimise battery life. This means apps that are not opened frequently are put to sleep after awhile. THIS KILLS ALL SCHEDULED ALARMS. Here's a helpful site which may be able to show you how to stop this: dontkillmyapp.com
If you're like me and keep forgetting turning your phone's silent mode off after college classes, or maybe after daily corporate meetings, why not leave this task to Quiet Time, and not be bothered by ads?
Quiet Time is simple application for managing your phone's silent mode automatically. Simply define a start and end time for your quiet time, and select the days of the week you would like your phone to be auto silenced. Once a Quiet Time is created, the app will manage the silent mode of your phone for you!
You can create multiple Quiet Times if you like, and the app will warn you if any of them overlap with each other, so that your phone will not go out of silent mode at an unexpected time. You can also select whether you want your phone to go into Vibrate mode, or completely get muted.
NOTE: Depending on your device, the silent mode might also trigger Do Not Disturb. This is unavoidable on certain device models as far as I know, for example a Pixel phone.