Q:

Repeat some action every x minutes between "A" a.m. and "B" p.m

How can I run for example local notifications? 
In UNUserNotificationCenter there is not repeat feature.
Maybe using NSTimer or something like this?
Why my code does not work as I expected 
let hours: [Int] = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24]
    for hour in hours {
        for minute in stride(from: 0, to: 60, by: 5){
            let content = UNMutableNotificationContent()
            content.title = "Title"
            content.body = "Body"

            var dateComponents = DateComponents()
            dateComponents.hour = hour
            dateComponents.minute = minute

            let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)
            let request = UNNotificationRequest(identifier: "timerDone", content: content, trigger: trigger)
            let center = UNUserNotificationCenter.current()
            center.add(request) { (error : Error?) in
                if let theError = error {
                    print(theError.localizedDescription)
                }
            }

        }
    }

A:

There is a repeat feature.
From Apple's documentation:
let content = UNMutableNotificationContent()
content.title = NSString.localizedUserNotificationString(forKey: 
           "Hello!", arguments: nil)
content.body = NSString.localizedUserNotificationString(forKey: 
           "Hello_message_body", arguments: nil)

// Deliver the notification in five seconds and repeat it
content.sound = UNNotificationSound.default() 
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 60, 
        repeats: true)

// Schedule the notification.
let request = UNNotificationRequest(identifier: "60_seconds", content: content, trigger: trigger) 
let center = UNUserNotificationCenter.current()
center.add(request, withCompletionHandler: nil)

Edit:
As also written in the documentation, you certainly have to have user permissions to post notifications:
let center = UNUserNotificationCenter.current()
center.requestAuthorization(options: [.alert, .sound]) { (granted, error) in
    // Enable or disable features based on authorization
}

Result:
Notification is posted every minute:

