Unlike FLASH memory which can wear out, the common RAM in PCs does not. HOWEVER there have been changes almost yearly in what RAM a new machine may use. I'll only note the short list of some names such as DRAM, FPM (all are varients of DRAM), EDO, BEDO, SDRAM, DDRAM, RAMBUS and others.
So the challange is not if the RAM is worn out but is it compatible with the new machine.
The answer is usually no.
I am buynig a new computer. I want to load it up with RAM, but before I buy a ton of new cards, I was wondering if I could reuse my old RAM cards. Do they wear down with time like a hard drive? Or can I just pop them out of my old computer and into my new one without worrying about performace drag?