JLCPCB charges a per-component-type loading fee for 'extended' parts, so a hobbyist's 10-component board can jump from $8 to $40+ in hidden assembly fees before they even see the checkout page

JLCPCB's SMT assembly service divides its parts library into 'Basic' components (roughly 698 parts pre-loaded on pick-and-place machines) and 'Extended' components (everything else in LCSC's million-part catalog). Basic parts incur no extra fee. But each unique extended component type adds a $1.50-$3.00 feeder loading fee because an operator must physically mount the tape reel onto the machine. A typical hobbyist board with an MCU, a few ICs, some MOSFETs, a USB connector, and a handful of passives easily includes 5-8 extended parts, adding $7.50-$24 in loading fees on top of the component cost, PCB fabrication, and base assembly fee. This matters because JLCPCB assembly has become the default path for hobbyists who can't hand-solder QFN, BGA, or 0402 packages — which describes most modern component packages. The sticker shock of extended part fees destroys the cost model that made outsourced assembly attractive in the first place. A maker who budgeted $15 for 5 assembled boards discovers at checkout that the real cost is $45, and the obvious fix — redesigning the board to use only basic parts — forces compromises on component selection, may require choosing inferior parts, and adds hours of redesign time cross-referencing the basic parts list against datasheets. The structural reason this persists is that JLCPCB's business model optimizes for high-volume customers who amortize the loading fee across thousands of boards, not hobbyists ordering 5. The basic parts list is commercially curated for the most common production parts (0402/0603 resistors, MLCC caps, common LEDs), not for the ICs, sensors, and connectors that make hobbyist projects interesting. There's no open-source tool that automatically suggests basic-part substitutions during schematic design, so every hobbyist must manually cross-check each component against JLCPCB's parts list — a tedious process that the EasyEDA-to-JLCPCB pipeline should automate but doesn't.