Team performance

Hi guys! I have a question..
Does anyone knows if it makes a difference in you team performance when you play a long time with the same players? For example is it beter to play a couple of seasons with the same players and train them hard. Or buy new players every seasons?

I prefer to have a basic squad of 7-8 players for 3-4 seasons and add to them, some new players every season.

LOL most of my squad with me for 5-6 season already....