Most bots, droids, and androids don't need to sleep. Though, Dolly is an exception. But then, Dolly's body is very unique - a one-of-a-kind prototype designed to be as human as possible.
I sort of think android 'sleep' might be akin to what some researchers now think human sleep is for and what explains our dreams...correlating and transferring short term memory to long term storage, shifting 'probably going to need this later' bits to ready use and archiving other things we might never need to recall into powered-down but on standby drives. Our dreaming is a way of clearing the registers then defragging and formatting them for the next batch of data, which is why we rarely remember more than glimpses of our dreams and they fade rapidly when the new day's information starts to flow in...and also why we get 'foggy' when we go without sleep for too long, 'buffer overflow' ;)
Most bots, droids, and androids don't need to sleep. Though, Dolly is an exception. But then, Dolly's body is very unique - a one-of-a-kind prototype designed to be as human as possible.