I didn't read the entire thread, but my 2 cents to the OP.
I guess
not reading the
whole thread could have been a good idea this time
Most of times I dive sidemount, also in open water.
In my opinion that describes a significant mayority of sidemount dives nowdays.
Usually I'm the only SM diver on the site and it makes me look weird to others.
I actually haven't met a local diver competely surprised by sidemount in a while.
A helmet doesn't add much to that.
Oh yes it does. You could read the whole thread to have an example, but be prepared to be horrified
When I entered my cave training, there was no question about wearing a helmet or not. Having one was the standard.
That's a significant local difference. Helmets are rarely allowed by cave instructors here.
I like the lights mounted on the helmet in order to have free hands, therefore almost every time I carry lights I wear a helmet.
Have to mention there that I carry and use lights on almost every dive.
Never go without primary and several backups and use about 10Ah in a normal week, half that with only training dives at novice locations in a week.
In very good weather and visibility conditions additional night dives use the same amount.
So far I have encountered just two disadvantages:
I would rather say I encountered dozens, but none outweigh the advantages.
1) it is more complicated to exchange a mask;
True. But how often do you have to exchange masks in reality. I practice with the helmet now, don't see a problem. The worst outcome is probably dropping the helmet.
2) I cannot scratch my head or touch it when freezing.
That one I very signifficant I think.
You also cannot correct mistakes with hoods, hair, bent ears as easily.
I had to take off the helmet a few times.
3) It takes more technique to dive with a buddy since you can't look at each other without blinding him.
I only found technological solutions, no technique to reliably avoid mistakes otherwise.
4) Light signals are not an option unless you have unusually agile neck muscles
That is what I like about the gosidemount mounting system, and also why I use a problematic hose routing.
Light signals are ok when you can turn the light at least in one direction (up and down in this case).
And since you have the hand at the light then anyway, you can also unclip it and use it for more complicated signaling.