Pep Guardiola has insisted that it would be wrong for Manchester City to rest on their laurels as there is no such thing as the perfect squad.
The Citizens are on course to win the Premier League title with a record number of points and are also in contention in three other competitions.
City's quadruple quest has been given a further boost this month as Kevin De Bruyne, Nicolas Otamendi and Fernandinho have all put pen to paper on new deals.
Despite his side's incredible form this campaign, Guardiola claims that he has his work cut out to keep each of his squad members happy.
"Otamendi, Fernandinho and De Bruyne have all extended their contracts and we are so, so happy that they are with us for the future. It is the best news of the past weeks," he told reporters at Friday's press conference.
"[But] you are never near [perfection]. If you believe you are okay for the next three years it is a mistake. The players who aren't playing regularly accept their positions, but in future maybe next season they won't accept and they want to leave. You always have to solve the situation year by year."
City have been tipped to strengthen their defensive ranks before the end of the January window, with Athletic Bilbao centre-back Aymeric Laporte rumoured to be their top target.
