Does everyone need a +1?

I was not sure what to flair this as, so apologies if this is the wrong category.

I’m starting to feel everyone expects to have a +1 when they’re invited to weddings, I never assumed so unless it specifically said so. (but then again i have not attended a lot of weddings). Would it be rude or just plain odd to not give everyone the option for a plus one? I’ve pretty much included all couples on the invitations, but only long term ones. And everyone already will have someone they know there so they wont be alone.

I dont want a ton of people my fiancé and I don’t know at our wedding. Not to mention, things are already expensive enough.

edit: wow i did not expect so many responses so fast. you all bring up very good points, but for the most part it seems most people are in agreement to invite long term couples as named guests, but if someone doesn’t know others at the wedding - give them a plus one.

I guess I will be making mg final decision Wednesday when i send out the official invites. I wish I could respond to everyone, but I am at work. Thank you for the comments!