Laura and others, here's the explanation of the idiom I used in yesterday's blog post:

"What you lose on the swings, you make up for on the roundabouts. Its origin is from the fairground. For whatever reason, the fairground owner may be losing money on the swings, but gaining it on the roundabouts. So the situation is balanced".

I've used this term for a while, and my MIL uses it all the time. I didn't know roundabouts weren't American English!

Thanks Lyn D. and Denise for stepping in with explanations while I was away.