IMPORTANT: to depart from Jakarta Soekarno–Hatta International Airport, you need to have your bags x-rayed first before you check in.
IMPORTANT: after you check in your bags, the airport sticks stickers on your suitcases, which may not come off easily. As a result, your suitcase may be marred permanently (like mine, sigh). Think about whether you want to use your best, most beautiful suitcase if you are flying through this airport.
IMPORTANT: the airport charges IDR150,000 for airport tax when you check in. Hence, DO NOT SPEND ALL YOUR MONEY.
On the plus side, ALL the airport staff are very polite and friendly.