Can someone give me some advice as to how I can change these three lines of 
  code into a single line??

  <xsl:for-each select="//client[not($clientid) or @ID=$clientid]">
  <xsl:for-each select="descendant-or-self::client">
  <xsl:for-each select="usage[@TOTALSENT > 0]">

just replace xsl:for-each by /


<xsl:for-each select="//client[not($clientid) or @ID=$clientid]/descendant-or-self::client/usage[@TOTALSENT > 0]">

David

-- 
http://www.dcarlisle.demon.co.uk/matthew

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