Didn't it used to be every year and a half or something, don't think it used to be two years mind, then again I can't remember fully.
I agree with the first poster to be honest, taking two years to make a solid PES will be more beneficial for everyone than making two average PES games in that two year time space. People still play PES6 online, doesn't that already speak volumes? Fair enough it might not be as financially profitable, but PES is declining in sales I believe at the moment anyway, whilst at the same time losing credibility at alarming rates. Something needs to change.
Personally I quite liked PES 2009, or the single player at least, obviously the online was completely broken. Whereas with PES6 on the Xbox 360, the single player was poor but the online mode was so damn good everybody was playing hundreds of matches, and still do, for good reason. But while PES 2009 was quite good in my eyes, that isn't good enough, the PES of old on the PS2 was simply amazing - we're not getting that anymore. It seems like we're being greedy but when EA can step it up (which rarely happens), then surely Konami can - whether it be one, or two years, if it's good people will buy it.