How does this "playing next door" thing work?

My daughter is soon to be 4 and a very social only kid. There are kids next door ages 8, 6, and 2. My daughter loves to play with them, if they're outside she will ask to go over and play. Should I let her go over? How often? I've told the neighbors to always send her home if they're sick of her but I feel very guilty because their kids never come ask my kid to play, and the playing always happens at their place.I'm friendly with the neighbors but not super close. I've told my kid she's not to go inside their home, I trust them and everything but I think it's a good boundary. via /r/Parenting http://ift.tt/2eXVT8E