[Dubdub]

The use pattern you outlined was good for old NiCad batteries of days and devices gone by. All phones these days, not just the BB (laptop computers and tablets too,), use lithium batteries, which do not like to get below 20% on a regular basis as that damages the battery. Keeping them topped up actually seems to make them run longer and last longer.

I always keep mine plugged in when in the office and sometime in the car, depending on the length of the trip and expected time away from a power source.