this is just going to be short and sweet. i use ebay everyday. not just to buy and sale but to have a look around. as i sale items i have noticed that i have had buyers tell me they have not recieved there item and demand there money back, which is fair but how do i know there not lying? that is why i charge for special and recorded post. doing that i have that slip of paper where i can just go on the royal mail website and enter in the code and then it tells you if the item has been delivered. simple. you can even e-mail the buyer (or seller if returning) with the code. so they can check too.
i hope this was helpful. cheers and all the best