How long do you research before you build?

For what we're currently working on it took us close to 3 months to finalise the idea. We explored so many problem statements before landing on this.

We have to research all the time)

Probably took 2-3 weeks of interviews, cold calling, and research before realizing I had a good idea to capitalize on. However, just because you start building, doesn't mean you stop researching. Always need to be aware of potential competition, new customer pain points, etc.