A way to answer it from your own data:
- For each strong move, note when the first pullback to your entry zone came: within 15, 30, 60 minutes, or later.
- Note how pullback trades did by waiting time.
A possible rule based on that: if the pullback hasn't come within a set time, say 30 minutes, cancel the plan and look for a new setup.
Why a time limit helps: without it, a pending order from 08:20 can still be waiting at 11:00, in a completely different market.
A worked example: an EURUSD breakout at 08:10 with a buy limit at the breakout level. If price hasn't come back by 08:40, the order is cancelled, even if price is still near it.
How long do you wait?