I have regifted a few times but only items I know I will never use. And I am always careful to make sure I am not giving the gift to the person that gave it to me. I think it is better to give the gift to someone that will use it instead of leaving it sitting unused.
Personally I don't like the idea to become a regifter because a slight mistake giving back a gift to who gave it to you, or to a common friend that had helped the person to choose it could cause to lose a friendship or to get hard feeling developing in the background. It's like you would not care about the time, money or feelings that a person put into a gift. Exception could be when you receive gifts from people you don't really know but had to give due to social conventions. However sometimes you may receive too much gifts, many of which could be repeated items, ugly items or something that you don't really care to keep, in which case I prefer to sell on eBay to get some money and avoid hurt anyone's feelings.
Yeah, sometimes I will also look to exchange a gift is there is a size or colour problem. But the person who gave me the gift doesn't always put the receipt in the bag, or doesn't provide it with the gift, and then asking for the receipt is a little bit awkward, especially if the gift giver is a little sensitive. They feel like they did something wrong, even though that is not the case, so I will just give the gift to someone else.
