A connector only becomes visible when it fails. Connection drops, project stops, cause unclear. While the problem was there from the start: the wrong connector for the application.
Dupont and pin headers: for the workbench
Dupont jumpers and pin headers are standard for breadboards, development boards and temporary connections. Fast, cheap and universal. And that's exactly their limitation: they're made for the workbench, not for a finished product.
A Dupont connection that vibrates, bends or gets pulled loses contact. Sometimes completely, sometimes intermittently — the worst scenario, because intermittent faults are nearly impossible to debug. For a prototype, Dupont is fine. For something going into a housing, travelling, or moving: use something else.
The MP006286 jumper wire kit (male-female, 150 mm, Multicomp Pro) is a solid choice for the workbench and prototype phase.
JST: compact, locking, reliable
JST connectors are small locking connectors you'll find on batteries, sensors and compact modules. They click into place, don't pull out unexpectedly, and are mechanically far more robust than Dupont.
The three most common series for makers are JST-PH (2.0 mm pitch), JST-XH (2.54 mm) and JST-SH (1.0 mm, the small Qwiic connector). Note: the pitch determines which connector matches which cable. A JST-PH plug won't fit a JST-XH housing even though they look similar.
Also check the maximum current: JST-PH is typically rated for 2 A per contact. For higher currents, look at a different series or a screw terminal.
Screw terminals: serviceable and strong
Screw terminals are indispensable when wiring needs to be replaceable: relay boards, power input, wiring that needs to be connected in the field. You attach a wire without special tools and detach it just as easily.
The downside is size: a screw terminal with 5.08 mm pitch takes up a lot of space on a board. For tight enclosures, 2.54 mm pitch variants are more compact, though less convenient for thicker wiring.
Current and mechanical load
Every connector has a current limit. That's in the datasheet, not on the packaging. For low-current signals it rarely matters, but for motor power or battery connections you need to take the limit seriously.
Vibration and movement wear connectors out. In projects used in vehicles, robots or outdoors, strain relief — a bracket or cable clamp that takes the mechanical load off the connector — is a necessity, not a luxury.
Practical guide
Prototype and test: Dupont and pin headers. Compact permanent connections: JST. Power, service points and external wiring: screw terminals. Mark polarity in your design: a connector that only fits one way can't be connected incorrectly.