Just to reiterate what some others have said, this is all about how you do your clubbing and how you rest up and refuel in between.
From my own experiences this was really highlighted by the difference between my trips in 2011 and 2012. In 2011 we would return from the club about 7AM, sleep for 4-5 hours and then be up for midday, not only enjoying the sunshine, but actually feeling pretty good. At no point in that holiday did I feel burnt out. 2012 was a different story. Drinking heavily after returning from the clubs. Not always getting proper sleep. I almost KO'ed myself 2 days in.
Everyone's different of course, and one of the things that I love about Ibiza above all, is the capacity to just keep going and going where you would just crash and burn at home. There's no way I could do 7 nights on the spin at home. In Ibiza, its possible. Sun, sea air, swimming pools and good vibes save the day.