In the pic below the extra connector cord that came with the battery charger to facilitate charging without having to remove a side panel. I thought it could be handy and I even added a fuse. After some five connect/disconnect cycles it already was unreliable. I removed it and connected the charger to the supplied longer cables again, the ones with the clamps. No big deal. But as I still use the same connector, the problem followed, so every now and then the cord connectors have to be tweaked. After what I've read here, I'm even more determined to replace them by another type. No more of the same, not even a better quality. I'm done with them.
Whenever you buy equipment, have a look at what connectors are on it and inspect the suppleness of the wires. The wires on mine are the cheap kind and stiff. As a matter of fact, the only supple wires on my bike are the silicone leads to the sparkplugcaps. Although you find these inferior connectors and wires usually on products of Chinese or Taiwanese origin, you can't say they're on all. I have a 30 year old automotive DMM, which has been used a lot, but still has the original silicone wires. Another thing to look at, is the casing. Is it hard plastic that will split on even the lightest impact or is it made of a more forgiving material?