How do you do business idea validation ?

Hi so im just wondering how people actually check if their ideas are good before wasting time or money on them. like if you get an idea you are hyped about, do you even do any market research to see if there is demand? where do you look for that kind of stuff, like surveys, talking to people, keyword research, social media or whatever? or do you just build it and hope for the best lol

Im just curious if most people actually research first or just send it. i see tools sometimes for keyword stuff or customer interviews, but never really one place that helps you gather and organize all that demand research together.

if you ever launched something before what made you feel sure people actually needed it?

keen to hear what worked or didnt work for you guys, thanks