This may seem trite, but if it's a good song I'm never sick of it. Yes, some songs are over done, but if they are truly good songs they are timeless, and the day will soon come when the 25th or 30th cover will be some wonderfully fresh rendition. For example, there was a time when just about every folkie I knew was singing Jesse Fuller's San Francisco Bay Blues. It came to the point that I would roll my eyes as soon as I heard the intro. But then I heard the song a couple of years ago performed by someone on the women's music circuit. She was young and couldn't possibly have been around back then. And I thought to myself, Wow, what a great song! I put it back into my own repertoire for the first time in goddess knows how many years.