Originally Posted by
zacster
I would say some of the brightest light are also the cheapest, and there is no reason they won't last. I have an XM=L2 light that will outshine anything I've seen. It cost $20, although it didn't come with a mount but I already have one. I also put a high output battery in it and I have yet to run it down but I'm not using it for cycling.
Actually it was $14. The specific one is no longer on Amazon, but there are others just like it.
Actually, there are two: Materials and workmanship.
If its a cheaper product then it stands to reason that the materials are less than high quality. Sometimes that matters i.e., plastics vs metal. Sometimes it does not. In the case of electronics you have everything from the cable to the type of light and the housing they are encased in. An HID is brighter than an LED but they don't last nearly as long.
Again, if you're riding straight and level on the road all day then something like casing might not matter. However, if you do mostly off-road riding and in adverse conditions then a HIGHER quality light and casing might be more reliable and save you money over time. Just think cheap metal flashlight vs plastics that are impact resistant and are water tight.
Take for example a cell phone. I have a very cheap cell phone and it runs hot. Not only that the battery runs out in a couple of hours. Thing is,
it works well enough for me since I'm not really that dependent on a cell phone use anyway.
Last but not least, there is the power cell. I have used cheap flashlights before and they start off bright but don't stay as bright for long. The case falls apart and the switches fail.