Replace your brush heads at least every 3 months. There is a coloured wear indicator strip on most heads (or sometimes the brush heads will turn from blue to white). Keep an eye on this, as you may need to replace them sooner or later than 3 months.
Cleaning your brush handle and heads is easy. In a spray bottle keep a mixture of 1/3 vinegar to 2/3 water. I spray my brush handle (and wipe it) before I charge it - this keeps your charger clean. I also remove the brush head and spray the bristles and interior of the head with lots of vinegar solution (I may be a bit of a germophobe). Make sure you rinse it well before brushing.. unless you like the taste of vinegar.
After a cold or flu you can spray the brush head with the vinegar mixture to kill any residual bacteria or virus. Listerine is also effective for killing bacteria- soak your brush head for a minimum of 20 minutes and rinse it well. Listerine will change the colour of your brush head.
Charging - for first use follow the manufacturer's instructions. This will affect how long your brush will hold a charge.