I personally think its having the right track in the right place, and sometimes there is always and older tune which is perfect for it. I'm very structured in my set thinking and if my more newer tunes doesn't fit I will look back to a great tune to fill it.

Recently I've been thinking of using Angel of Death (Hennes & Cold mix) and The Sound of Rock by Hennes & Cold in my hard style sets as they are both hard and old tunes which still have a lot of authority.

Obviously there is no specific way forward with how you do your sets, but in my opinion there will always be older tunes that can't be ignored in my box amoungst the new!