Point taken Juuule!!
Cat 64 - save for some dire circumstance, I'm not in the habit of accepting favours from anyone unless I can repay them in some way: that's just the way I was brought up. Why is that strange?
That doesn't necessarily mean I "keep score" in the other direction though - I appreciate the difficulties larger families face balancing work and extra curricular commitments.
However, it is simply good manners to reciprocate where you can I think.
And yes, if we are so busy at work that I can't reciprocate for a while, then I tell dd that she/we have to cool the play dates for a bit.
And the attitude of some on this thread "oh I am doing you a favour by 'lending' my child to you for the afternoon" irks just a little bit frankly.
Yes, I am inviting them to play with my dd, yes your child may be lovely, yes they and my dd may get on wonderfully well together thus relieving me of "play" duty
but
(a) I do genuinely hope your child will have a good time too and I often go to quite a lot of effort and sometimes expense (prep of various craft activities or cooking food they like or outings etc) to ensure that he or she does!!
(b) sometimes your child may not always be an angel (same as my dd) or she may be ill or in need of some other help
(c) it is a huge responsibility looking after someone else's precious child and making sure they are safe and content
Frankly, when others do it for me, I am grateful. It's a bit churlish to be otherwise isn't it??