I did mine in one, and it is a long slog, but it's nice to get it over with rather than having to wait and find out if you passed.
Also, I believe you will be examined on the whole flight, so if things went perfectly the first time and then you made a dog's dinner of arriving and landing the second time, I think you might fail?? Not 100% sure if that's right.
Of course my arrivals and landings are perfect every time
