Leave Notice
This should be covered in your leave policy but it’s worth mentioning again here: Having a clear rule on how much notice should be given for leave will make life a lot easier for you and your team. After all, you don’t want to be told that an employee is going on a two week holiday with only two days’ notice!
A general rule of thumb is to ask for the notice period to be at least twice as long as the time being booked – so two weeks notice would be needed ahead of a one week holiday. This will vary depending on your company though, so don’t be afraid to set rules which work better for you; if you set your shifts at the beginning of each month you might want all leave requests in before that. If you plan it a week at a time you might be happy to have a more flexible policy, though.
Bear in mind that the rules should apply to you as well; if you need to ask employees to take leave or to cancel their holiday then you should give them at least the same amount of notice as you’d expect from them. Likewise, if you’re refusing their leave request you should let them know as soon as possible. You don't want them to assume that no news is good news!