Don't have time (today) to go searching (and also I'm a bum).
Our guest list is funny. I've pretty much divided my (previously-thought-to-be-small) guest list into chunks: my "must-haves" - the people without whom any celebration of my happiness would feel incomplete - and everyone else, who is secondary but would feel snubbed if they weren't invited while others in each circle (aunts/uncles, cousins, more distant relatives, etc) were. If I can get away with it, my side of the guest list will have my 12-13 must-haves and nobody else. The oldest young cousin would be 14 by the wedding, and if we get a small wedding as we'd like it won't even be an issue.
FI's is simpler - he has 12-13 people, total. His extended family is not really involved. Now, this is before speaking with FILs about the guest list, but it seems that the consensus is that's it.
My question is that my initial plan was to offer +1s to every unmarried guest, whether or not they had a SO. However, this was when our guest list was comprised of my 12-13 (which includes everyone's +1) and his original 6 that I knew of. ALL of them are adults over the age of 18. Yesterday, we added some other people who are important to him/his family. It makes me gleeful that he did - I just have one question.
Two of his teenage cousins, both of whom will, we think, be under the age of 18 (but close to it) and still in high school at the time of our wedding, are in relationships. I had not really thought of a cut-off age to allow a +1 as until last night I did not think it would be an issue. I would go with 18, myself, or if your invite is actually addressed to your parents, you, and your siblings as opposed to your own invite separate from that of your parents. However, I don't want to slight anyone, or be rude, and the general thought on here seems to be that if two people are in a relationship, they get to be invited with their SO.
(Yes. My wedding is way far off. But I am building a budget and looking at ideas, and I actually do need this information this early just to make me not crazy when it actually does come up.)