The average hard disk drive last about a year now anyway, lol, so the paranoia around SSD lifespans is ridiculous.
On SSDs, the act of "defragmenting" is frowned upon. A fragmented file on a SSD doesn't really mean much, (not getting into the details of custom algorithms by manus) don't "defrag" an SSD.
Not that this is an end-all answer, but if you use Windows 7, you don't have much to worry about.