If it's anything like 2000 and 2008, the monthly fast stoch should stay oversold no more than 15 months. However, in the case of 2000, this doesn't necessarily mean bottom; that came at 24 months. The true bottom is to be confirmed by blackcat's "Whale Jumping Out of the Ocean" indicator, which I highly recommend. If the channel from 2008 breaks, QQQ ~260, there should be panic selling until at least the midpoint of the macro channel, ~160.