If you haven't updated your system since installing FM 2012.09, the amount of 700+ packages is totally reasonable. It's been half a year, and there are many software packages that have been updated, be it for security or bug-fixing reasons or because of feature enhancements. Many package updates were requested, as were new applications.
Also, KDE consists of at least 218 packages (I just took a quick look at what packages in the repository have version number 4.10.1).
Users are usually encouraged to update once a week or so. If the time between updates is too long, it increases the risk that something could break. Not necessarily, but who knows.
If everything goes well (which I expect), you'd be better off updating regularly
EDIT: µT6 was quicker (once again)