General Overview
How yo set units (length, degrees, time etc.) –
The CG Essentials
How to Measure object mode measurement tool
Snapping to grids lines, vertex, etc.
Measurements – In Edit Mode
Another video for edit mode
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General Overview
It is easy to overlook measurements when you first use Blender. But at some point you will reach the level that you need to know precisely wher and what size your objects are.