Jonny6 - 7:47 pm on Jan 10, 2011 (gmt 0)
As already said above, it doesnt run out at all, the exclusivity to it has. Having said that, the actual pagerank algo has changed considerably since.
When considering linking to a site; the toolbar pagerank is a useless metric of Google's determination of the quality of that site.
A site categorized as bad can still show a very healthy toolbar PR for quite some time.
The toolbar pagerank for low quality sites are not updated as quick as better quality sites, so consider that many sites havnt had a toolbar update since April 2010 and that update was based on the actual pagerank from months before, so its not rocket science to realise that the pagerank reported could be a year out of date.