Friends of DH's begged kindly volunteered to have our impeccably behaved springer instead of him going to kennels when we went away. The first time was a couple of months ago. I wrote them anal very detailed instructions about everything. They said he'd been very good and were desperate to have him again. He came back a few pounds heavier, but I didn't really mind that.
So he's been back three days after a week log stay. His recall has lapsed - it's always been instant and totally reliable, now he is maybe 90% reliable. He is begging for food at the table. Refuses to follow commands that have been completely solid ('to your bed', for example).
He is also a bit whiny, trying to get upstairs where he's never allowed, not settling properly.
I guess I have to do all the stuff again that I did to train him in the first place. But he's three years old and it seems so long ago. I also only had one child then, not two!