Football can be a pretty transient business, out of the door at one club one week, in the door at another the next.
Cambridge United boss Neil Harris and his director of football Mark Bonner will need to ensure the door they go through at Priestfield Stadium on Boxing Day (15:00 GMT) is marked ‘visitors’.
Harris spent 20 months in charge at Gillingham, which included relegation from League One, while Bonner’s eight-month stint produced 15 defeats in his 28 games.
Since then Harris has been at Cambridge, who he left for Millwall, before returning to the Abbey Stadium in February where once again he was powerless to prevent relegation – see what I mean about the transience?
His second stint with the U’s came at the same time as former boss Bonner’s appointment as director of football – are you keeping up?
They are just one point outside the play-offs but only four ahead of their opponents.
Gillingham’s recent seasons have been mirror images – impressive starts followed by a downturn in form and failure to even trouble the top seven.
Four managers in under two years tells the story and although Gareth Ainsworth’s arrival in March inspired a 21-game unbeaten run, time off for the boss to recover from heart surgery and more indifferent results means they are once again in danger of flattering to deceive.
BBC Sport will have live text coverage of all the EFL action on Boxing Day.