Thanks for your answers, gents.
It worried me somehow. I read it another gun related forum, but who knows if the one who so said was a Glock fanboy or similar. The PX4 fits inside what I'd call the "combat pistol" category, and it is supposed to fire plenty of magazines before cleaning is required.
FYI, when we were issued our 92FS, we were told this weapons were sensitive to dirt and that they were best kept clean. I've shot like 300 rounds through mine with no issues, and it's my intention to shoot another 300 to see what happens and where's the limit. I usually clean my pistol after each range day, but it's good to know how many magazines you can fire before you start having problems.