When does a 'pullback' become a 'reversal' for you?

I've been trying to get better at identifying trend continuations versus actual reversals, especially in intraday charts. Sometimes what looks like a healthy pullback on, say, a 15-minute chart for a long setup ends up just tanking further, blowing through my stop. I try to watch for volume cues and candle formations, but it often feels like I'm seeing what I want to see in the moment. Is there a specific confluence of factors or a clear-cut level you look for before you shift your bias from a dip-buy opportunity to a confirmed trend change? What's your mental checklist?