It is great but exhausting having lots of visitors. Thoughtful visitors know that and know bad days might mean you get cancelled at the last minute. They take it with good grace. So my tip would be to acknowledge that upfront and give the person you are going to see 'permission' tell you if it is too much. Just say "it will be great to see you, but if the battery power is too low just tell me and I'll come another time" Oh, and it is the thoughtful visitor who doesn't get bounced!