Yes you can recharge often, some of my cells get charged more than once in a day! Store around 3.6v(around nominal voltage) for long periods. No need if its going to be stored for a week or 2, but if its going to be months.............year then storage voltage.
The i4 although a good charger, its a little long in the tooth and slow with 4 bays full of cells. If your light collection is going to grow with v54 lights etc etc, then its worth investing in another charger(or 2 or 3). Ideally one that will support 1a on all 4 bays, better with options of even higher rates(usually limited to 2 bays, not all 4) of 2a+. This rate is ideal for the larger 26650 cells............
I would at 1st get used to the light and find out how much use your getting and to what the V of the cell/s. Little bit of a pita at 1st but saves taking up too much thought down the line. If you know you get roughly 1.5hrs of use and your down to 3.*v , then you may use it 20m a day.............then on the 4th day you may get into a habit of topping off(just rough examples).
If i use a light for 10m or so, i wont top cell off as its a bit of a waste of time for me personally. So i will top off after several uses and can usually get it pretty close (guessing voltage).
Back to chargers, the advantage of a charger with a digital V read out really is user friendly. Pop cell in and straight away get a V reading, this in itself learns you and keeps it user friendly. (no breaking out a multi meter each time friendly).
