How do you decide when it's time to leave a stable job for something that actually excites you?

I've been in my current role for about three years. The pay is decent, the hours are manageable, and my manager is pretty reasonable. On paper it looks great. But I dread Monday mornings and I catch myself watching the clock every single afternoon. There's no growth happening and I stopped learning anything new about a year ago.

I've been looking at opportunities in a different field that actually interests me, but the transition would mean starting at a lower salary and rebuilding my reputation from scratch. The safe part of my brain says stay put and be grateful. The other part says that spending another three years feeling this disconnected is a real cost too, just not one that shows up on a pay stub.

I know this is a common situation, but everyone's circumstances are different enough that generic advice only goes so far. For those of you who have made a leap like this, what finally pushed you to do it? Did you regret it, or was the shortterm hit worth it? And for those who stayed in the stable role, do you feel like you made the right call? I'm genuinely trying to figure out how other people have thought through this because I feel pretty stuck right now.