If you're asking this question, chances are you're either thinking of using save the date cards to announce your wedding, or you're not sure who's going to make the final guest list just yet. Well, let's be clear: it is not a good idea to send out save the date cards to anyone who won't receive a proper invitation; it'll likely offend, and could even ruin a friendship. Here are three reasons why sending out a save the date card with no follow-up invitation is a bad idea:

1. People make plans

From booking time off work to making travel plans and looking up hotels, many people will plan early for a big event like a wedding. They might even be out buying new outfits for the occasion - it's not every day we get an opportunity to dress up. If you send out a save the date and then don't follow up with an invitation to the wedding, it's no surprise anyone who's already made plans or even spent money on attending will be annoyed to say the least.
Can You Send a Save the Date and Not an Invitation? - Confetti Sparkle Foil Save the Date Cards

2. You might get some phone calls

It's understandable that, as your wedding day approaches, some people who have received save the dates but not invitations might get in touch with you, assuming it might have been lost in the post. If you then have to explain that they aren't actually going to be invited to the wedding, you could be having an awkward conversation. It’s better to avoid this situation by dodging this ‘save the date mistake’ in the first place.
Can You Send a Save the Date and Not an Invitation? - Eucalyptus Garland Save the Date Magnet

3. They'll probably be offended

If you send someone a save the date and then don't send out an invitation, they'll most likely be offended. Probably much more so than if you just hadn't sent anything about your wedding in the first place. It's ultimately quite rude and doesn't really take into account the amount of effort that other people might put in if they think they're going to be invited. So, if you're unsure of your guest list, then simply wait a little longer before you send out save the dates - or, only send them to those people who are definitely on the invite list.
Can You Send a Save the Date and Not an Invitation? - Forest Love Boutique Wedding Invitations