There are two generalities that can be applied to all asset bubbles:

1. Bubbles inflate for longer and reach higher levels than most pre-bubble analysts expected

2. All bubbles burst, despite mantra-like claims that "this time it's different"

The bubble burst tends to follow a symmetrical reversal of very similar time durations and magnitudes as the initial rise. If the bubble took four years to inflate and rose by X, the retrace tends to take about the same length of time and tends to retrace much or all of X.

If we look at the chart of the Case-Shiller Housing Index below, this symmetry is visible in Housing Bubble #1 which skyrocketed from 2003-2007 and burst from 2008-2012.