Inflate soccer balls to the pressure of 6-8 PPI (pounds per square inch). A pressure gauge will tell you when the air is enough. Under or over-inflating a soccer ball will shorten its life in one way or another. When under-inflated, the ball will not be resistant to the impact of kicks. On the other hand, over inflation will stretch out the bladder and put pressure on the panel stitches.
Latex bladders are one of the best materials when it comes to ball construction. However, with latex bladders, air won’t last as long as butyl bladders and will need more attention for proper inflation. Butyl-blend bladders hold in the air much better, but they are harder and less receptive in play. Mid-priced balls will usually have a mix of butyl and rubber. https://www.youtube.com/watch?v=c1SVcjYY6TE