Note that the Check For New Builds link is gone from Update and Recovery in build 9926. That is because it is now done via Check For Updates. You set how often you get notified of new Builds via:

Click on the Notifications Tab
Click on All Setting at the bottom right
Click on Update and Recovery
Click on Advanced Options
Under Choose How Preview Builds are Installed select Fast or Slow

Mine was reset to slow and I changed it to Fast