We've had Christmas after Christmas that they feel the need to buy stuff and spend a certain amount on us, even though we don't need or want anything. So we have boxes of unopended tools and appliances that we may never use.
Argh... This causes me all sorts of anxiety! DH and I live in a townhome and have been very vocal with family members about how much de-cluttering we have done lately. As a result, this past Christmas, we received very little "stuff" .. And the things that we did get were all very practical items. It was such a relief!
30 y/o FTM here and I'm also concerned about receiving too much baby "stuff" that is not really necessary. Again though, because we have been so vocal about being short on space, I don't expect that we will receive too much that we won't use. Plus we registered for new OR used stuff (encorebabyregistry.com) - and only for the basics - which helps get the point across.
(I was especially thrilled when my mom indicated that she will be more likely to gift our LO cash for her RESP along with a token gift, vs. excessive and fancy brand name toys that are likely to clutter up our home. Love!!!)
Anything that you DO get and have no use for (assuming you can't return it or exchange it in store), find a spot for it in storage and either sell it (yard sale, Craigslist, mom to mom sale, or consign it) or donate it to a good cause. You could even save some stuff to regift if you know of friends or family members who are also having a baby soon.