In his Method I system, a volatility breakout strategy, Bollinger say to enter a trade when the bands expand from their tightest squeeze, i.e., lowest Bollinger Band bandwidth, in six months. Unfortunately, he never seems to say what kind of chart he's using. Should we enter following the tightest squeeze in 6 months based on a daily chart (which would be about 132 periods) or a weekly chart (about 24 periods)? I never trade using daily or weekly charts. I'd like to use the squeeze strategy, but can't figure out how many periods to be looking back. I wish Bollinger would state the look-back time in periods rather than months. Do you have any idea about how many periods to be looking back for assessing bandwidth?