How do I insert two edge loops equally spaced from the edges? I find myself doing this quite a lot in Blender 2.8: Add temporary centered edge loop (Ctrl+R click, Esc), then use Offset Edge Slide (Ctrl+Shift+R - I think this is the default?) to generate 2 mirrored edge loops that are equal distance from the corners of the shape, then delete the temporary center edge (Ctrl+X).

Hopefully this isn't too confusing - the point is to quickly create two edge loops that are identically spaced from the edges. This seems like an extremely useful task. My question is - Does Blender have some mechanism to do this in one step? The ability to create 2 edge loops and edge-slide them away from each other simultaneously?

I'm okay with using add-ons if anyone is aware of a tool that does this.

EDIT

After posting, I starting playing around with the loopcut_slide shortcut and may have came up with exactly what I wanted. I haven't fully tested this, so it may completely fail at something later. But so far, it seems pretty good.
It creates two edges (in one click/drag), and moves them toward/away from each other simultaneously.





If you guys have trouble seeing the shortcut, here are the most important settings:


Shortcut Command: mesh.loopcut_slide
Number of cuts: 2
Factor: -0.5 (this starts them in the center - use 0.0 to start at default spacing)
Single Side: Enabled (this was the magic checkbox that made it work)
Clamp: Disabled (otherwise, they cannot move to the center)


The only issue so far is that it is easy to accidentally slide the wrong way with clamp turned off. So it may be better to leave that on.

For anyone not familiar with creating custom shortcuts, you just go into User Preferences -> Keymap -> 3D view -> Mesh (Global) -> scroll to bottom and press add new, expand the new entry and type in mesh.loopcut_slide into the text box. Then set up the options as above.

EDIT 2

After playing around with this some more, it appears this setup does not work as well as I hoped. When the enclosing edges have strange angles, the cut-slide does not perform the way you would expect. So my vote goes to Lemon's suggestion of using Bevel after adding a single loop cut. It works perfectly in all cases 
except when your model has UVs (edit/correction: bevel does work well with UVs). I will update this if I manage to stabilize this crazy shortcut.
CtrlR for the first loop.

CtrlB to bevel it using the percent option.