Every manager wants to do the best by her employees, so saying "no" to time off may be one of the most difficult things you'll have to do. Here are my thoughts on what to do when you cannot grant these requests.

Develop formal procedures
Make sure your employee policies answer the following questions:

• When can requests be submitted? Specify a time frame or dates by which the request must be submitted, and, in general, the earlier the better. It may not be fair to specify a certain time of day that you'll consider requests (in other words, first come, first served). When I worked in a hospital, employees who came in early in the morning of Jan. 2 hustled to file their time-off requests for the year, effectively "blocking off" their desired dates before the staffers scheduled to arrive later that day or the next day could even submit a request.