Well, I have created a python script, which checks the number of uncompleted tasks of tasque and displays it using pynotify periodically. My question is how do I implement this timer. I can think of two things. A Cron job to execute a python script periodically or using a python script which uses a gtk loop to call the specified function for checking periodically.
Cron job. It's more likely to be "in line" with actual time, since it's a more stable and time-tested choice. It's also less demanding on resources than using a loop in Python since it doesn't require a constant Python interpreter process, and is probably better optimized than pyGTK (choice is mature, stable software vs. less mature, less stable).
Gtk loop or Cron for timer