For me I was always conscious of it happened to my uncle. He has lived in Germany for over 15 years and he has lost a lot of English. He teaches on a part time basis some evenings and works in a company full time so that is why he is losing it.
I saw that happening to him and vowed that it would never happen to me. My wife felt the exact same as she knew this one teacher who taught kindergarden for seven years and he's English was really bad. So we download and watch a lot of TV shows. I watch the Irish new regularly on
www.rte.ie We only speak in English (that's all we know) so that helps too. It's another reason why I want only to teach adults or university students. The only thing that I will lose will be the local slang but that changes all the time.