When should you build your own tools instead of just using a SaaS product?

Hey everyone, I've been thinking about this a lot lately. When does it actually make sense to build our own tools and dashboards instead of just paying for a SaaS product? Obviously, there are money concerns and you dont want to build something just because it wasn't invented here. But then you run into limits with SaaS, or those fancy features get way too expensive. Is it about how big the team is, or needing super specific performance? Or maybe it's more about where the data lives and security stuff? I'd love to hear what you all have experienced and any ideas you use to decide.