It entirely depends what you are thinking of using them for in the first instance.
But whatever you are using them for you must test many different lengths of moving average as well as different bandwiths (EG 1 std dev, 1.5 , 2, etc) and different exit points (eg at the moving average? at the upper or lower band? at the moving average minus or plus some fraction of a standard deviation). And there are many other frills and additions you can experiment with.
I believe I am correct in saying Bollinger devised the bands as a counter trend trading system. Many use the bands as a trend following system however.