Rechargeable AA and AAA batteries can be reused many times and this will help to reduce the disposal of normal single-use alkaline batteries. If 5% of the local population switch to rechargeable batteries, this would prevent the annual disposal of more one million single-use batteries (assuming each person throws away five single-use batteries a year).
Switching to rechargeable batteries also helps you to save money. A pack of four AA alkaline batteries costs about S$2 and can be used only once, whereas a pack of four rechargeable batteries and a charger costs about S$40, and the batteries can be recharged and reused more than 500 times. If you switch to rechargeable batteries and recharge them 20 times, the purchase cost between normal and rechargeable batteries would break even.