Speculating Fibs

I noticed lately a lot of stocks retrace their fib levels - 23.6, 38.2, 61.8, 78.6 - in ranges that with highs in an uptrend or lows in a downtrend that haven't been reached yet, or don't exist, hence speculative:

Here, for example, the SPY retraced at the 78.6, 38.2 and 23.6 levels without reaching the low of 102.69, so that level would be used as a potential buy/cover level on more downside