can a team become bored of winning?

just starting my 5th season at spurs and we look like we are struggling against the better teams and are not lethal enough. the last 4 seasond have been very successful so my question is can players become bored. i have not made a big signing in over 2 years instead gathering a core group of star players in the first 2 and a half seasons then turned my attention to youth. can players become disinchanted if i never make big signings.

i've noticed that i need to keep a regular turn over of players to keep them successful. if i keep the same team for a number of years, they do start to go down hill, even if they are all around 25-29 years old still and in their prime.

i guess it could be complacency.

buy 1 or 2 new players that can instantly compete for a first team place and if a player goes through a bad patch, you'll have someone else waiting in the wings. keeps them on their toes.

I've read an interview with Ole Solskjær, and he said following from his playing career in Manchester United. If the team failed to win the league, they didn't buy any player, because the determination to win was still in the squad, but if they won, the squad needed some new blood to get new competition in the squad.

If you win, the team will perhaps become too relaxed if you win everything, and therefore you should purchase someone who can lift the squad, either by getting some driven guys in to push the team on forwards, or someone who can sharpen the fight for the position, perhaps a creative flairy winger to challenge every attacking role in the squad.