All of our rechargeable LED lights use lithium-ion batteries. The great thing is the batteries aren't really going to be limited by charge cycles - feel free to charge your light no matter what the current charge is. What you do need to watch out for is how you store them.
Before putting away any Lezyne light for an extended period, it's important to have at least a 50% charge on the light. The reason for this is there's a slight trickle drain on the battery when it's not in use. In 3-6 months, depending on the size of the battery, the drain might deplete the battery. If you're using the light, it has a governor on it to prevent the battery from getting too low, but if the lights off, there's nothing to prevent that. If the battery gets too low, it'll be ruined.
The best thing you can do with your light: use it!