Was reading up on SSD performance degradation and came across this (old) article from AnandTech. Good one! Explains why SSD performance degrades over time and what TRIM sorta does to improve things. The unfortunate truth seems to be that SSD performance will slowly degrade over time and the only way to restore performance then is to do a secure erase (see this PCWorld article too).
Update: I don’t want to make a new post just to mention this so I’ll update this older post of mine. Here’s a post from Scott Hanselman on why Windows defrags your SSD drives and how that’s not such a bad idea. Upshot of the matter is this: fragmentation affects SSDs too, though not as much as HDDs (because SSDs have no performance hit unlike HDDs). With SSDs fragmentation affects performance in that (1) there’s a limit to the number of fragments a file can have, and once that limit is reached it can cause errors when writing/ updating; (2) more fragments means more time spent putting these fragments together when a file is read. To avoid these performance issues Windows automatically defrags SSDs once every month.