What's worse than training staff who leave?

Not training people who stay. Every day your people go to work they cost you money, make you money or both. The obvious cost is the wages you pay them. But what about their impact on the performance of the people around them? What about their impact on the perception and loyalty of your customers? On your brand? Are you giving your people the opportunity to perform at their best? 

Sure, you could 'save' money by not training your people. But what does that 'saving' cost you?