An official documentation may or may not hint about the first Windows 10 PC / Mobile Redstone update timelines. As you can read in the above screenshot, it seems, 1602 Build version will be somehow important. The document mentions 1511 and if you remember 1511 version brought the first Mobile RTM update release and Windows 10 TH2 update. In the same vein the document mentions, future updates and specifically gives example of 1602, which means a built made in February and should be out in February 2016. Well, this might be just an example cited or may be more than that.
New update versions release periodically and will include product updates, and might also introduce new features you can choose to use (or not use) in your deployment. Different update versions are identified by year and month number like 1511, which identifies November 2015 (the month when System Center Configuration Manager was first released to manufacturing). Future updates, beginning in 2016, will have version names like 1602, which indicates an update that was first available in February of 2016.
Redstone is the successor to current Windows 10 Threshold project and next year we may see two Redstone update waves hitting PC and Mobile.