Dual card cameras: change cards often or use lg sz and keep shooting?

I use 12MP cameras, 16GB cards last all day.

depends on scenario...

at weddings, 32CF and 64SD in both 5D3 bodies... RAW to both
my butt was saved once by dual-card body... I recommend it to everyone...

when doing family/personal stuff... 32CF for RAW, 8GB Eyefi in SD for JPEG.... and then just auto xfer jpeg to ipad... much easier for friends/family to see shots, etc... and can do quick edits and post to FB or whatever else I want to do with these shots

I don't understand this reasoning. Sure, there's less chance of losing the lot, but there's also more chance of losing a part. I mean, if you use six cards as opposed to two, you have 300% more chance of losing some files.

Moreso, actually, because you're trying to keep track of a bunch of cards, which gets confusing.

These days, with the duel card slots, it makes sense to just shoot on larger cards. I use 32 gb cards, but may switch to 64s. I find two 32s (one for each camera) is about the right amount for a shoot, and if I use larger cards I tend to shoot a bit more wastefully. But bottom line: with instant backups on the 5d3, its silly using a ton of smaller sized cards for safety.

This.