Sometimes it’s uncanny as to how price respects the Fib levels…..and for that matter why?
Have a look at this bullish Gartley pattern on the daily time frame of the AUD/CHF

One can see that each and every wave of this pattern has formed at the precise Fib levels of the Gartley.
Is there a reason why price reacts at such levels, and keeps going from one level to another to complete a pattern?
I don’t think one can give a proper explanation, as to why it happens.
But then, as traders, let us take advantage of the fact.
If we know that price has a high probability of respecting these levels, let us plan our trades in such a way, that we can get an edge.
Taking this particular example, once we had the pt. D form at a confluence of 2 fib levels…precisely, we could anticipate a reversal to the upside here.
Hence we prepare for long trades and define our price targets.

We must accept the fact that nothing works all the time, and however precise a pattern may be, there is every possibility that it could go wrong.
As traders, we are here to take profits, and hence one must take the profits off the table when price gives us the opportunity.
We can do that, only if we know the possible price targets.

The price objective of a Gartley pattern is always the Fib projection 127.2 & 161.8 of the wave A-D.
But we can define certain in between levels for taking profits.
One such level is a measured move distance of the wave B-C. If we add this distance to the low of D, it gives us an initial profit taking level.
And one can see that this level coincides with 2 other levels of resistance -
(a)    The 78.6 fib level of the wave A-D.
(b)    A previous level of resistance (as shown by the red line)
Since this becomes a strong level of resistance, we can expect some pause/consolidation/pullback in the price movement.
This could even turn into a reversal, which is precisely the reason that one must take profits.
Now, since the Gartley pattern has been quite precise, we have a fair expectation that price will fulfill the next targets.
Hence, we can plan our trades accordingly and still look for longs after any pullback to the downside.
If at all, price does not complete the other targets; we have still walked away with some profits.
And I would rather have small profits in my account, than being proved right all the time.
Sunil.