If you haven't received the latest Android 4.4 KitKat update for your Nexus 4, Nexus 7 or Nexus 10, it's best to exercise some patience instead of heading to the Internet or forums to search for unofficial methods of getting the update faster.
One of the most popular methods recommended is to clear the Google Service Framework data. While the method works for some users, Google engineer Dan Morrill cautions users about using it
According to Morrill, clearing the Google Service Framework data will change the primary ID that Google servers used to identify your device. He compares it to doing a factory reset without losing the data.
In addition, this method disrupts the connection to Google Cloud Messenger (GCM) and will have negative side effects on your device such as messing up the push notification system, and invalidating the tokens used by any app that relies on GCM.
In case you don't know, almost all Google apps use GCM. Hence, in the event that you clear the Google Service Framework data, you have to login and logout from the Play Store account and your Gmail account may not get new mail notifications for some time.
In a nutshell, Morrill claims that this method will cause a lot of issues on your device without your knowledge. He recommends a safer method for eager users - adb sideloading the update package.
Adb sideloading is a new command introduced by Google in the earlier versions of Jelly Bean where it allows users to update their Nexus devices through stock recovery without having to root or flash a custom recovery.
Morrill also explained in a separate post on the process of rolling out OTA updates for Nexus devices. In the first 24 to 48 hours after an announcement on the availability of an OTA update, only about 1% of devices will actually receive the update.
This is done to ensure that the update has no bugs or errors. After going through the return rates and error reports, Google will then proceed to issue the update to more devices from 25% to 50% to 100% over the course of one to two weeks.
Morrill - "Rollouts are conducted in phases. Typically they start at 1% of devices for around 24 - 48 hours; we watch the return rates and resulting device checkins and error reports (if any), and make sure nothing looks wrong before sending it to more. Then typically it goes to 25%, 50%, 100% over the course of a week or two.
What the percentages mean is that when your device checks in, it has a 1% chance (for example) of being offered the OTA. If it doesn't (randomly) get an offer, it will never get an offer until the next batch.
IOW, once your device checks in and gets turned down, that's it until the next batch. Mashing on the "check for updates" button just causes your device to check in again, and get automatically turned down again. Think about how that makes your device feel! WON'T SOMEONE PLEASE THINK OF THE PHONES?!
That said, once the new batch does start, hitting that button does give you a new roll of the dice -- but once. Since devices usually only check in for system updates every 24 hours (I think? Certainly on a many-hours basis) this can get you your shot sooner than it would happen on its own.
So, mash away. :) Just be patient, and mashing on it more often than once or twice a day isn't going to gain you anything."
Edit: also, keep in mind that this isn't first-come/first-served. You're not racing other devices to get your slot in the current batch, or something.
While having the latest Android version is thrilling, messing up your Android device due to your impatience will make matters worse. As the saying goes, good things come to those who wait.