In reply to purplemonkeyelephant:
"I see it more as, why use snapgates?"
because they're lighter (noted this doesn't matter to you)
because they're more versatile
because they're less prone to problems with gates sticking and freezing
because when two are used back-to-back they're even stronger and more secure than screw-gates
"When I bring my second up to the anchor... Why not maximise all your security points?"
because it just isn't necessary, a belay of sound anchor(s) clipped with snap gates is easily secure enough
"They also can be used as spares if you need to leave one behind"
some would say you've got money than sense if you're choosing to leave behind screwgates rather than tat, maillons or snapgates
"It's not doctrine, if I don't see the point of it I may not, but in most cases I need all the mental reassurances possible, and weight vs risk usually has only one winner in my climbing. "
As I've said it's not just about the weight. The risk is considered and removed/reduced to an acceptable level by first choosing suitable anchors and then using them to construct a belay that's safe enough, which for me means one that is going to hold. It's perfectly possible to do that with single snapgates on each anchor but if you want to maximise security then you should be using two wiregates back-to-back rather than one screwgate (unless of course you want to use two screwgates back-to-back). Also, if safety plays on your mind so much then consider this; do you use screw-gates on both ends of all your runners when you're leading? If not why not? The krabs on your runners are far more likely than those on your belay anchors to move about and get loaded across the gate or gate open. Granted a runner could fail and another one hold you but at the grades you're climbing you'll probably have already hit a ledge or the ground before your next runner catches you. For you to worry so much about the belay for bringing your second up is like saying that it's okay for you to kill yourself by ballsing up your runners leading but it's not okay for you to kill yourself and your mate by ballsing up your belay.
In reply to SenzuBean:
Sorry for drifing slightly off topic.
To answer your original question about what other people use, here's what I normally carry
for single pitch...
1 x small light HMS for belay plate (
https://www.google.co.uk/?gws_rd=ssl#q=petzl+attache+3d)
1 x small light HMS for tying off belay anchors at the body (
http://www.v12outdoor.com/product.php/6641/mammut-bionic-mytholito-sg-basal... easily takes two clove hitches, three at a push
0 x extras for clipping into anchors, I just use whatever's left on my harness
for multi-pitch where I'll be the setting up belays before the top...
same two HMS plus a few phantom wiregates
possibly one extra screwgate (D shape) for stuff like trainers/camera/waterbottle
For ease of use with gloves in winter, or at places which often need more anchors for the belays, I'll sometimes swap the small HMS for this bigger one (
http://www.v12outdoor.com/product.php/2414/mammut-bionic-mythos-hms, basically the same as the Boa). Not a big deal though, sometimes I've meant to do this then forgotten about it and it wasn't ever a problem.
In reply to all:
I'm offshore and it's been a slow few days.