Not done all at once (7)
I believe the answer is:
gradual
(Other definitions for gradual that I've seen before include "Step by step" , "Proceeding in small stages" , "Developing in small steps" , "(Of slope) not steep" , "Little-by-little" .)
I believe the answer is:
gradual
(Other definitions for gradual that I've seen before include "Step by step" , "Proceeding in small stages" , "Developing in small steps" , "(Of slope) not steep" , "Little-by-little" .)