Broke a jumper wire with the first pin I tried to use.

I wouldn't recommend using the cheap wires included since they tend to have loose connection.

The jumper wires were not working

Might lose one or couple wires.

Some took a lot of diagnosing to figure out that the wire was bad and others just wouldn't work at all because the relay was garbage

The colorful jumper wires in the kit, to interconnect with the UNO proved to have extremely fine wire between the end probes resulting in a resistance of around half ohm, which makes those jumpers a source of error when trying to make accurate measurements

Turns out that *19* of the included wires were bad, and I used 2 of the bad wires to light an LED

But that is a large number of bad wires

The included large breadboard and jumper wires don't quite work together; the wires fit loosely and don't always go straight in