Originally posted by ewok hunter
it seems that they can also gain awairness over time if they don't have regular memory wipes
This is the standard idea.
Think of it as your computer.
As you work/play/surf/whatever else you do on your PC, stuff gets logged into memory. Cookies, old files, websites in your "favourites" menu that you haven't visited in years, all sorts of stuff. Every now and then, you have to go through it and throw out all the old data.
This is how droids work. As they function, they store data. Little quirks from their masters, things they've seen, memory logs of their day-to-day life. For the most part, this is useful ("Hey, A-3K, where did you put that crate of turbo-capacitors?"). Naturally, this mass of data can be transfered (just as I could, if I wanted to, copy my cookies and recycle-bin onto a new machine).
Eventually though, droids start to go beyond their programming. Why and how this works still aren't clear, but they do. THis is a problem because droids are, after all, machines, and you don't want your property deciding that you're not doing things right.
Memory-wipes are a convenient way to avoid this "problem," as they just delete everything except the droid's hard-wired programming (and anything that the owner specifically sets aside; most mem-wipes are done professionally, to avoid end-user screwups).
Basically, droids are the perfect slaves. If they disobey you, you can just erase their personalities (or even have them scrapped and replaced).
They're just things, it's not like they're actually people