If want to prolong the battery life, get a smart charger that can charge each battery individually (normal charger need to pair the battery to charge), monitor battery level and cut off charging when the battery full. I use this 4 slot one: https://shopee.com.my/LiitoKala-Lii-402-186...2830.2155526821 since I have many rechargables, but there's 2 slot and 1 slot also.

Can use on many type of rechargable battery. Not sure how long can use, but I use almost 1 year still doing fine. Just sometime need to rub off the dust from the metal of no use for long time. So far still okay. My 1000mAh take about 5 hours to full. It can detect what type of battery it charges and adjust the voltage and current accordingly.