This slowly happened to my original nexus 7 tablet. Sad. Eventually its just too slow to use. Ten minutes or longer to bootup, etc. Of course its a gamble, will people crack the screen or kill the battery before the memory is destroyed, if so who cares ship it.

You can play games for awhile stripping stuff out of memory so it can live in the fast area but eventually its speed drops to approximately zero even if all you have installed is the kindle app at which point I tossed it.

There is a lot of cargo cult about there about wiping the cache over and over supposedly helps in the sense that the owner feels they're doing something, although all they're doing is wasting the last few R/W cycles left.