I rarely need antihistamines myself, although I do keep an antihistamine cream around for bites and stings that's usually enough in my case.

But my mum is allergic to cats, and to a less extent dust mites. My dad gets *horrible* reactions to insect bites (of the sort that occasionally mean having to visit local hospitals when on holiday). And my sister gets bad hayfever, and so does Mike. There are always antihistamines in my house too :)