It's a MIL one I'm afraid. She does the present buying on behalf of her & FIL. It is very much a leisure activity (going shopping), they tend to go for a lot of days out as they are retired. However this has been the status quo for some years. FIL isn't interested in buying presents (he's not against it, she is just much more interested). She is aware we have gift lists, on Amazon, she has one as well. She expects her gifts to be purchased largely from there, but tends to buy other people's gifts from wherever she sees something she fancies buying. She has previously bought DH the same book three Christmases running.
This year, once again, DH's & my gifts have all been donated already. We have never said anything, because it would be rude. We have, however, on previous occasions, asked her / them not to buy us sweets etc, as we are trying to be more healthy, & I plain don't like sweets (am exceedingly picky when it comes to sweet stuff, I'd rather have a tiny bit of something really good, or just go without). I have also got health conditions which are triggered by various foods. We both got a large package of cheap sweets. We have previously been instructed, in no uncertain terms, not to buy her sweets, as she has health issues. We abide by her request, but she doesn't.
She asked me a few days ago how I liked X present. Honestly, I didn't know what to say. We don't have a great relationship with them, although they're actually not aware of this - MIL has a staggering lack of boundaries & is pretty narcissistic IMO. I'm fully aware that this is probably colouring my (our) view of the situation. DH is just as fed up of it as me.