One way is to give more interesting work and/or work that is a natural possible progression in the employee's career. That technique helped my company woo me over into staying, along with a modest salary bump (although I was seeking much more - career progression mattered a lot to me).

From a personal perspective - I've turned to the quit mentality due to boredom after my first job after not having enough to do, and at my second job I converted over after immense deadline pressure for half a year when combined with significant underpayment (extreme frustration).

The best pre-emptor would be to be proactive in addressing these problems. If your company is exerting too much pressure on developers, then you probably did a poor job hiring enough employees or incentivizing them enough - I'm looking your way startups.