NZcaver wrote:harrym wrote:You don't need a second light on your helmet that's as good as your primary. You just need a small light that will allow you to get out of the cave or to find a better light in your pack.
This is a matter of opinion. What might work for you might not be the best solution for other cavers.
Here is a differing opinion about having a pair of high quality, redundant lights on the helmet at all times.
No, it's not really a matter of opinion. You don't need a second light on your helmet that's as good as your primary.
I agree with the person in your reference that you should have a redundant light, not a "backup." My 2nd source is just as good as my primary, by intent.
But you don't need that redundant light source on your helmet at all times. You just need a "backup" light to get into your pack and find your redundant source, and replace the dead primary on your helmet. The other reason for a small "backup" light on your helmet, as I mentioned above, is for vertical work.
In actuality I carry 4 sources of light:
1 primary
1 redundant primary (fits in the same position as the primary)
1 carbide (heat and light)
1 helmet-mounted "backup"