How long before your money doubles? There is a shortcut so simple you can do it in your head: take 72 and divide it by the yearly growth rate.
Money growing about 6% a year → doubles in about 12 years (72 ÷ 6)
Growing about 9% a year → doubles in about 8 years (72 ÷ 9)
Growing about 12% a year → doubles in about 6 years (72 ÷ 12)
Try it. Put 200,000 into a SACCO that grows your money about 9% a year. In 8 years it is 400,000. In 16 years, 800,000 — and you never added a single extra shilling. Time did the work.
Where you keep money matters
Cash hidden under the mattress grows at 0% — and 72 ÷ 0 never doubles. Worse, prices keep rising (inflation), so that same cash slowly buys less bread each year. Money sitting still is quietly shrinking. Money that is growing is on a clock, ticking toward double.