I say, leave them wanting more. It is best to make a departure on a high note.
When students want more when you end the class, it is the best all-round applause. You know you are an effective and well-loved teacher when they hang around instead of running out the door at the earliest opportunity. When they sit there staring with disappointment that you are bringing the class time to a close, it gives a teacher a great sense of fulfillment.
I may have mentioned it before, but it is worth mentioning it again. I have been so fortunate as to have had that experience. I have left eager students still engaged in study and wanting to engage with the teacher behind in the classroom at the end of the period. It happened today. So great was there disorientation and disappointment at me wrapping it up at the usual time, that I thought the clock was wrong or that I had missed something. Mouths opened, they sputtered, "But, but...Are you leaving now? Is it over?" Fantastic!
I should have had the wisdom and gumption to have timed my departures better in the past. That is a well learned lesson after having dragged my heels making a decision, failing to let the signs register in my brain, and hung around too long in various situations, like the stalling in deciding to move out and find a new life in the months before I came to Korea. I came here when I had to, instead of earlier when it would have made my life more comfortable, less embarrassing and desperate, not to mention less stressful and tumultuous. No more! I am going to leave Korea when things are at an all-time high for me, personally--as students and co-workers cry out for me to stay, as the offers to continue to teach here proliferate and become more insistent, as my teaching gets better and better. That's the wise way.