Once you have completed an object that forms part of a large drawing, and have moved it into the correct position, get into the habit of Applying the Location as well as the Rotation and Scale.
Applying Rotation and Scale
If you change the scale of an object, always apply that scale by typing 
to avoid strange things happening with bevels. See this article. The same goes for Rotation. Once you have Rotated an object into position, always apply that Rotation. See this article.
Applying Location
When you Apply the Location, the object origin in Blender gets moved to the World origin.
There is the option to apply All Transforms which simply applies everything: Rotation, Scale, Location, Modifiers etc. but, be careful – if you have unapplied modifiers on the object, you may not want to apply them – either now or ever – so getting into the habit of applying All Transforms is never a good idea.
So, to do it properly, first, apply just the Rotation and the Scale by selecting the object and typing and clicking:
Then apply the Location. Select the object and again type and click:
Once again – this is important – “Why do two steps?” you might ask. Could you just apply All Transforms?
Ahhh. yes… but then the modifiers would also be applied!
We want to apply the Location because this sends the object origin back to the global origin of 0,0,0.
Why do we want to do this? Well, you don’t have to, but it’s a very good habit to get into because an object often gets accidentally moved without you noticing it at the time. To see at a later stage whether it was moved or not, select it and check that the origin is exactly on the world origin of 0,0,0. If the object has been moved, it’s easy to move the object back into position quickly.
If you look at the Item tab of the “N” menu it should ideally look like this:
Scale applied should look like this- The X, Y and Z values in the Location fields should be 0
- The X, Y and Z values in the Rotation fields should be 0
- The X, Y and Z values in the Scale fields should be 1
