For sure avoid all those cheap aftermarket props on Ebay and amazon. Only the best from Master Airscrew. Because we all know, DJI don't make their own props....they buy them from someone else, too.
Hi,
Up to now, I've built tricopters, using the cheapest parts so I could crash and repair, and I broke many props. I did upgrade to carbon fibre!
I've just bought a mini copter, with quite flexible blades, that seem 'unbreakable', but I'm sure...