I have students in and out of my house a lot when I am home. I enjoy this but not everyone does. Set the rules. If my gate is open and my sign says open they can ring the doorbell. I sometimes ignore them if they violate this. They often send a message before they come to make sure I am home and accepting visitors.
Students visit our home quite often and usually unannounced which can be difficult at times. You may find you have to ask them to leave as they don’t always pick up on signs that you are busy or want to go to sleep. Generally speaking the visits are welcomed though and can lead to some interesting informal discussions. One student visits regularly to help us with our Chinese which is very useful.
We have visited several students homes which is a great way to experience the culture first hand.