Desk research against primary sources, with the issuing authority linked where a page states an official fee, rule or deadline.
The 15–25% annual premium for furnished is the ongoing cost; the AED 30,000–80,000 to furnish yourself is a one-off. Whether unfurnished works out cheaper depends entirely on how long you stay, since the upfront outlay is fixed but the annual saving compounds every year you renew — a short posting favours furnished even though it is more expensive per year, because you never reach the point where the numbers cross over.
A furniture allowance from your employer removes the trade-off entirely, since it is designed to cover exactly the upfront cost that makes unfurnished unattractive for a short stay — in that case there is no reason to pay the ongoing furnished premium at all. Selling furniture when you eventually leave also recovers only a fraction of what you paid, which is worth factoring in before assuming the unfurnished route pays for itself as cleanly as the year count alone suggests.
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