How to test product demand with a button before writing code

I spent three weeks building a heavy export feature because three outspoken users kept asking for it again and again. After we launched it the numbers told me that than two percent of our active users actually used the new export feature.

For the big idea I chose a cheaper path. I put a button for the requested feature in the interface. When a user clicked that button a pop‑up appeared that said the feature would arrive soon and invited the user to give feedback.

Than forty percent of users clicked the button proving that there was real product demand before I wrote one line of backend code. That proof saved us weeks of wasted engineering effort.

I always measure real user clicks on a placeholder interface before I commit development resources to a feature.

What method do you rely on most to separate product demand, from loud feature requests?