Beware that the Dubai check-in closes 75 minutes before the flight departs, even if travelling with handluggage only. No machines, be prepared for three rounds of X-rays.

If you're going to be a regular visitor it's worth applying for an e-gate card (although the benefits of this have declined with the opening of T3 and you should always keep the printed receipt to avoid getting trapped in no-man's land. I speak from experience).