Most students obsess over getting the perfect fillet or chamfer on their first try. That's not what's costing them.

The real mistake: building parts without a design intent.

Here's what that looks like in practice — a student sketches a bracket, dimensions it off arbitrary edges, and it "works." Then a spec changes (hole spacing, wall thickness, mounting position) and the entire model breaks. Sketches fail, features go red, and they end up rebuilding from scratch instead of changing one dimension.

What experienced CAD engineers do differently:

1. Sketch from a fixed reference (usually the origin or a mounting datum) — not from whatever edge happens to be closest.

2. Use dimensions and relations that reflect how the part will actually change — if a hole pattern needs to scale with plate width, drive it with an equation, not a hardcoded number.

3. Name your features and sketches as you go. "Boss-Extrude12" tells you nothing six months later when a client asks for a revision.

4. Model like the part is going to change — because in real engineering work, it always does. Specs shift, tolerances tighten, manufacturing methods change.

This is the single biggest gap between "I can use SolidWorks" and "I can be trusted with real design work" — and it's exactly the kind of thing we drill in the CAD Mastery Program through actual project rebuilds, not just tutorial-following.

Curious — for those of you already working in SolidWorks/Fusion/AutoCAD, what's a modeling habit that changed how you build parts?