How do you test if a feature is actually needed before writing code?

We’ve all fallen into the trap of spending weeks building a highly requested feature, only to watch it sit there untouched after launch.

People love filling out feedback forms and asking for complex options but their actual daily habits rarely match what they type in a survey.

Now before writing any code, we try putting up a fake button or a simple mockup just to see if people actually click it. How do you usually validate an idea before committing your engineering time to it?