Ever noticed how a brand new can of balls feels amazing, but a week later they bounce like a stone? It's not your imagination — tennis balls lose pressure over time.
The Science Tennis balls are hollow rubber balls filled with pressurized air (typically around 12 psi inside). When you open the can, the inside pressure starts to slowly escape through the rubber. The felt covering wears down too, which changes the ball's flight.
How Fast Do They Lose Pressure? A new can of balls at atmospheric pressure will lose about 50% of its bounce within 1–2 weeks of regular play. After a month, they're essentially "dead" — barely bouncing and feeling heavy.
The Solution Instead of buying new cans every week, you can keep your balls at optimal pressure. A ball pressuriser re-inflates them back to 22 or 29 PSI, so they bounce like new for months. It's like giving old balls a second life.