         NSLayoutConstraint(item: ageLabel, attribute: .CenterX, relatedBy: .Equal, toItem: view, attribute: .CenterX, multiplier: 1, constant: 0).active = true
         NSLayoutConstraint(item: ageLabel, attribute: .CenterY, relatedBy: .Equal, toItem: view, attribute: .CenterY, multiplier: 1, constant: 0).active = true
 
-        if let age = viewModel.age.value {
-            ageLabel.text = String(format: "%.12f", age)
-        } else {
+        if viewModel.age.value == nil {
             ageLabel.text = "Please open Countdown and set birthday"
+        }
+
+        viewModel.age.producer.filter({ $0 != nil }).observeOn(UIScheduler()).startWithNext { [unowned self] age in
+            self.ageLabel.text = String(format: "%.12f", age!)
         }
     }
 }

import UIKit
import NotificationCenter
import CountdownKit

@objc(TodayViewController)
class TodayViewController: UIViewController {


    //MARK: UIViewController

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)
        viewModel.active.value = true
    }

    override func viewDidDisappear(animated: Bool) {
        super.viewDidDisappear(animated)
        viewModel.active.value = false
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        preferredContentSize = CGSize(width: 0, height: 50)
