Why each instalment earns differently
Your first deposit sits for the whole term. Your last deposit sits for a single month. A recurring deposit is therefore a series of separate fixed deposits with staggered start dates, and the maturity value is the sum of all of them compounded individually.
This is why the effective return on an RD is always lower than the headline rate suggests. If you deposit AED 1,000 a month for twelve months at 5%, you have not invested AED 12,000 for a year — on average you have invested it for about half that.
Compounding frequency matters
Most banks compound recurring deposits quarterly. Monthly compounding produces a slightly higher maturity value at the same nominal rate. When comparing products, check the compounding basis as well as the advertised rate.
Early withdrawal
Breaking a recurring deposit before maturity usually triggers a penalty, commonly one percentage point off the applicable rate, and interest may be recalculated at the rate for the period actually completed rather than the contracted rate.