Oh don't worry, I didn't hang around to breath it in 🤣
Charging at a lower rate does help preserve the life of the battery.
This is the rule I follow:
From an FPV website...
"The safest way to charge a lipo battery and the one that puts the least amount of strain on your battery is to charge at a rate of "1C" or 1 times capacity. A 1C charge rate means that the current will charge the entire battery in 1 hour ( assuming you are starting with a fully discharged battery around 3.2v ). For example, if you had a 1000mAh lipo, to charge at 1C you would set your charger for 1 Amp. If you had a 500mAh battery, you would set your charger to 0.5 Amps. If you have a 1500mAh battery, you would set the charger to 1.5 Amps."