Sentence:  While expensive in time and <WSD>involving</WSD> a great deal of adaptation on the part of the worker ( in terms of his willingness to leave the sanctity of his office and enter actively into the client 's life ) , techniques of accompaniment were found to be of tremendous value when in the service of specific preventive objectives . 
Meaning of the word marked with <WSD> tags:  require as useful, just, or proper