Desk research against primary sources. Figures are traced to the issuing UAE authority and linked on the page.
Timing this around your actual departure date rather than a calendar month avoids paying for a service you are no longer using while your final bill is still being calculated on the old address. Subscriptions are different because they renew on a billing date that has nothing to do with your move, so the 30 days before departure is there to make sure a renewal does not land after you have already left and stopped checking that account.
The UK/US bank card matters most in the gap between opening a UAE account and it becoming fully functional for online purchases, hotel deposits and anything that checks a billing address against a home country. Closing it early to tidy up before leaving is the mistake — keep it open through the 3–6 month window even if you rarely use it, since reopening a closed account from overseas is slower than simply not closing it.