class App
{
    public bool IsRunning {get; set;}
    private Thread houseKeepingThread;

    public void Start()
    {
        this.IsRunning = true;
        this.houseKeepingThread = new Thread(ThreadFunc);
        this.houseKeepingThread.Start();
    }

    private void ThreadFunc()
    {
        while (this.IsRunning)
        {
            DoWork();
            // wait for 30 seconds
        }
    }
};