@bemax hm, I was required to replace one rotor blade during beginning. - I started the drone and during landing it did not land on the spot where it was supposed to but a few feet away.. I did not react properly (beginners fault and on ground there was grass and a small stone I was not aware of - a bit of one blade was chopped of so I was glad to have a spare one.
This is the reason why I mentioned the take off and landing platform need to be even and horizontally. Then the GPS and return to home function - and recognition works.
No need that our fellow Halliwell Jones must make the same experience. This (minor) accident was my fault. pure grass doesn't hurt the drone - except it may chop off some grass during landing.. Dont use the drone as a lawnmower..