People need to bring everything they need with them when they come over.
Why do they need to bring things with them when they come over?
I can't provide everything that people need when they visit.
It is good to let people know that they need to bring things they might need with them before they visit. It might help to have some basic items at your home for guests.
I can't really provide anything so they need to bring over whatever it is that they will need for their stay.
If you can't provide items you guests might need, it's fine to let them know that. It's important to tell people that information upfront so that they know what to expect when they visit.