The joy of placing a bombproof ice screw 100 foot above your last dodgy tied off rock peg is one of life's great unsung pleasures.
The aprov, aplocv, approc (sod it) method of drilling two screw holes so they meet and can then take a threaded length of cord is good, but difficult to execute in a raging whiteout while hanging off an axe with one hand a couple of hundred feet off the deck.
It is however an excellent technique for retreating from a good ledge on a mountain, an action usually preceeded by erm....slight errors of personal judgement.