There’s never a “convenient” time to apply updates, but while you may be taking it easy at this time of year, chances are good that others are not: script-kiddies and others with nefarious intent, knocking loudly at your door (forum-spam) or quietly checking the windows (looking for vulnerabilities).
As always, do backup first. For end-users thinking “it can’t happen to me” (hard drives never choose a good time to crash), it’s a good excuse to backup !
Certainly with Windows, do check for updates. There have been many important security patches of late.
But the latest Apple updates are comparatively just as important.
Backup, then update.
As a general practice, always wait (!) at least a couple days on Apple updates, check for any unexpected outcome(s) for others (and always take forum posts with a truckload of salt), and then download and use the “Combo” updater.
Update your Acrobat (Reader or Pro) and Flash plugin. Very important.
And if you use WordPress (as we do here, in case you haven’t noticed), update that too (in case you didn’t notice the latest important update):