Is SPF 30 good enough, or should I use SPF 50?

Yes, SPF 30 is good enough. SPF 50 blocks only about 1% more UVB rays (98% vs 97%), and most people don’t apply enough to get the labeled protection anyway. What matters more is applying generously, reapplying every two hours, and not skipping days. A bottle of SPF 30 you actually use beats SPF 50 you hoard.