Length = depth only. It sets how deep each drawer reaches front-to-back — it doesn't touch width or height, so you stay free to build as wide and tall as you like, and every drawer in one setup shares the same length.

• Simple rule: measure the deepest thing you'll store, then pick a length whose inside depth (shown in each description) is a little bigger.
• The trade-off: shallow = less filament and print time, and you see everything at a glance; deep holds bigger and longer items but hides what's at the back.
• Not locked in: you can print a fresh set at a different depth later for a separate setup — nothing here is permanent.

Truly torn? 185 (171mm inside) is the versatile default that handles most everyday items.