Hey everyone

This is my first post on this board as I need some advise on how to proceed with envelope addressing.
My issue is that I have a bunch of adults (40+) who still live with their parents on my guest list and from what I've read, each adult in the household should get their own invitation. In one instance, there is a family (husband and wife) with 4 adult children still living at home. Am I really expected to send them 5 save the dates and 5 invitation suites? That just seems like overkill and a ridiculous use of resources/waste.
Has anyone else had this dilemma and if so, what did you do?
Edited to add: IDK if this means anything, but single adults are not getting +1s (only married or engaged adults) and no minors are invited.
Re: Do people really follow invitation etiquette 100%? Am I really expected 5 invites to 1 household?
Also, this is going to be to your benefit. Mail gets missed and mis-sorted. By addressing invitations specifically to those you are inviting you have the mail most likely to be given to the intended recipients rather than getting it mixed.
2) If you have guests in a relationship who are not married or engaged those partners also need to be invite. A "plus one" is not a requirement but it is necessary for anyone identifying as in a relationship to be invited with their partner. If in the above situations there are adult children living with their parents and they have a boyfriend or a girlfriend then you'll need to name the boyfriend or girlfriend on the invitation's inner envelope (or just the outer if you aren't doing inner envelopes).
3) At this point if you're still months away and haven't sent STDs yet it's advised to factor that your single guests will be in relationships by the time your invitations are sent. It ensures you have sufficient space and a budget to feed everyone rather than face a rough surprise as your wedding approaches.
That said, I think you could put all the separate invitations in their own envelopes, and then put all of these envelopes in one large envelope for mailing and put the postage on that if they are all going to the same address.