Comment 2 for bug 495758

>From my experience, it is a certainty that letting the XML files grow
with no bounds and no cleanup features will definitely impair
performance in a significative way down the line; now, I'm not sure at
what point it will be really apparent. Up until recently, GTK did not
trim the ".recently-used.xbel" file, and it inflated to huge proportions
over the years (hundreds of thousands of lines in my case), and
applications such as gedit ate the CPU and took over 5 seconds to save
(instead of saving instantaneously) because they had to write to that
file.