Sentence:  Since it is not far from Viareggio , he will visit Puccini 's house , as he never <WSD>fails</WSD> to do , to pay his respects to the memory of the composer of La Boheme , which he considers one of Puccini 's masterpieces . 
Meaning of the word marked with <WSD> tags:  fail to do something; leave something undone