to occasionally do sth that you used to do a lot so that you do not lose your skill at it :
She retired last year but still teaches the odd class to keep her hand in.
to occasionally do sth that you used to do a lot so that you do not lose your skill at it :
She retired last year but still teaches the odd class to keep her hand in.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005