I use my lights pretty much all year round. Less in summer, but still probably twice a week. In the winter it’s an almost constant charge/use/charge cycle.

how much charge should they have if not used for a few days?
How many times can I expect to charge a battery before it goes a bit rubbish?
I assume it’s not best practice to run the battery completely flat?

I’m using an assortment of Exposure lights, BTW.

Teach me about 18560 batteries please

I once read a guide about this in one of the mtb mags, not sure which one though. I think it said to keep the batteries in the fridge…but like you, I have Exposure lights, so don’t fancy putting the full lights in there for fear of damp/condensation. The article also explained how much charge is lost over a given period.