I think it depends what it is to an extent but I'm actually pretty comfortable with either option for people coming to mine. If it is a playdate then I basically expect people to not be exactly on time because well, kids. They nap a bit longer than normal or need a toilet stop or put their shoes on the wrong feet. And without kids well, life happens. Sometimes you don't realise how long the drive will be or you get held up by xyz that you didn't plan for. I do understand that for a dinner, being on time can become important to the flow but then, I don't see why a good evening needs to be perfectly timed. I've never been fussed on putting on a show lol. I mean, I'll try to be organised but I'm not going to worry about friends or family seeing me in the middle of prep or with toys on the floor or whatever other reasonable this could happen before visitors situation. But then I don't own make up or need to do my hair so there isn't that to worry about. I kind of think I'm human, you're human and neither of us are perfect so let's stress less about trying to pretend otherwise, what kind of relationship would that be? I'd just feel so anxious constantly trying to play a part, rather just be natural and enjoy those who accept me as is.

For going to other's places I try to plan to be there early but have something to do to kill time if necessary (petrol, read book etc) so you can get there right on cue but then I don't think I've been to anything without kids since having kids so well, kids.

If forced to choose, I think late is better than early as it would catch people less off guard. A text to let them know if possible (not always if you're caught in traffic and can't use your phone etc). And apologize upon arrival.

This is all in regards to somebody's house. A formal function, wedding, play, restaurant reservation or other such event is different. I'd always make a considered effort to get there with plenty of time to spare.