How should a team leader choose their development style? They should make their decision based upon the solidity of requirements. In principle, agile methodologies are great when a team does not have solid, nailed down requirements. In many cases though where requirements have been ironed out it might be fine to go with a traditional waterfall approach. My suggestion is that teams make the best of both. If you are operating with a more traditional approach, then it is still possible to mix some Scrum in there. Stand up meetings are a great way to briefly communicate issues, successes, or short comings. Regardless of your teams current development methodologies, remember that communication is key!