As we've gone off onto currency.. currency is not just hours either, you can fly a lot of hours that gain you nothing, or less hours that work you hard.
The problem with aviation is that it's difficult to set absolute rules (if you want them to be useful). You need to be honest with yourself about your ability at any given time, and self regulate - take responsibility. Which is not a popular concept in today's society, there has to be a rule, and someone to blame for everything (and in saying that, suprisingly I'm not an old git!)
For example, of late I've flown something around .5 just about every weekend for the last 2 months in various tailwheel aerobats. My handling skills are pretty well practised. My nav is more questionable, but it's not a lot of hours. 8 months ago I flew 40hrs in 4 weeks round the outback of australia in a C172.. with mostly 4hr legs my handling wasn't that hot. My nav was (fortunately) doing pretty well!