Starting at the beginning of May eBay made a change to the requirements for your listings to qualify for the Top Rated Seller 20% final value fee discount and icon badge. The old policy was that you needed to offer a 14 day return policy to qualify for the TRS benefits. The new policy requires you to offer a 30 day return policy. The other requirement of same day or one day handling remains unchanged.
If you are a TRS you will want to make sure you update all your listings to offer this 30 day return policy. Your return rate should not be affected much since this new policy is still within the range of the eBay Money Back Guarantee policy, which has not changed. The 30 day return policy may seem excessive for used and collectible goods but since you are held to the standard of the eBay Money Back Guarantee you might as well change your official return policy and take advantage of that 20% discount.
If you are interested in the requirements to become a TRS check out this post.