You have a point... but when everyone else has access to the same good tunes... you might get bored of being the same as everyone else?
Also if you have played them reguarly then might have got a bit bored of it, and something new might have come along?
Think joofs latest column in the m8 mag says it all, that djs now find it harder than ever to be original. So maybe thats why the play upfront as possible?
I pulled out veracocha - carte blance for Fluid, and Push - strange world for most of my gigs. Age shouldnt stop you playing tunes... but i dont really know many djs who do let it stop them.
Although on that note, i seen john kelly (first time i seen him aswell, and he wasnae all that) in ibiza and i recognised every tune he played and was quite bored tbh... its nice to hear new music and continually hear the newest tunes imo.