Most people simply aren't willing to buy stock when a single share is a hundred or more dollars. The company in question decides when the stock will split and what the ratio will be. Note that many companies choose to simply double the number of stocks during a split, but that's not always the case. Many different ratios can occur. So should you bail out when a company is approaching a stock split?
It's actually a pretty good time to be part of the shareholders. Consider this scenario. A company splits stock at a 2 to 1 ratio. That means that they've now doubled the number of public stock they have available. But it doesn't mean that they're suddenly offering new stock for sale to the highest bidder. It means that the number of stock you have has now doubled. What does this do to the price? The company's stock value must remain the same immediately after a stock split.