Even for the most generous of hosts, guests can occasionally overstay their welcome. When a friend has stayed at your home too long, you'll naturally want to send the message that it's time to leave without offending or straining the friendship. By confidently sending the message that the situation itself requires them to leave, you can make enforcing your boundaries less stressful.
In traditional rules of etiquette, it's considered rude to ask guests to leave directly. Whether or not you feel it's appropriate to keep with this tradition is up to you, but it's also worthwhile to consider your guest's expectations. When friends are visiting, you can probably expect that a little more honesty is okay, but older and more traditional visiting friends might find direct requests to leave awkward and embarrassing. To avoid risking offense, try to send subtle hints before you resort to asking your friends to leave explicitly.
When having friends over, let them know from the beginning how long you expect them to stay. With formal gatherings, put an end time on the invitations. With informal gatherings, let your friends know by saying something about your availability when making the plans, such as, “I'm only free until 10 p.m. tonight, but I'd love to do something until then.” This way, when the time approaches, you can indirectly remind guests by saying something like, “Well, it looks like it's about that time.”
Have good excuses on hand for why you need friends to leave at a certain time. In the evening, this may be a matter of getting to bed early for engagements the following morning. During the day, you may need to leave the house to run errands or have other obligations at a set time. Let your friends know what's going on and when and give gentle reminders when the time approaches.
If all else fails, you will need to be direct with your friends about wanting them to leave. In this situation, be assertive and assume that your guests have stuck around because they're unaware that you want them to leave. This will make things less awkward and send the message that while their presence is welcome, you simply can't continue to entertain at the moment. Apologize for kicking them out, but be confident and assertive. Use humor and be lighthearted about the matter. Keep the focus on you and your need to have an empty house. Don't say anything that puts the focus on your guest, such as, “You need to leave.” Instead, say something like, “Sorry, folks, this was fun but I'm going to have to kick you out now.”