resize - Scale drawings in Illustrator, maintain proportions of line weights and effects

My problem is that when I scale down my drawing, the line weights stay the same, blotting out the artwork. If I scale up, the line weights become too thin. I've noticed that parametric effects don't scale together with the drawing.

How do I scale drawings in Adobe Illustrator and still maintain the proportions of line weights, gradients, and effects such as offset path?

Answer

In the Preferences > General area, make sure Scale Strokes & Effects is selected.