as and when vs as long as

as and when

conj

  • as soon as 

as long as

conj

  • While, Since 

  • Used other than figuratively or idiomatically: see as, long. 

  • Provided that, if, assuming (depending upon some condition or requirement). 

How often have the words as and when and as long as occurred in a corpus of books? (source: Google Ngram Viewer )