I agree with Manolo^ that policies should be in place regarding vacation days, PTO, etc. Additionally, I think it’s important for the project manager to encourage communication between himself and the members of the team. Being able to trust your project manager and teammates can go a long way in planning. I think in terms of vacation days, these should be planned well in advance and the person leaving should inform the project manager and the rest of the team as soon as possible so that accommodations are made. I also am of the belief that if you as a member of a team know that something needs to be completed, you should complete that before leaving for vacation or delegate so that someone can do so in your absence. I think during meetings all goals should be reviewed, timelines examined to make sure everything is on track. The project manager should ask if there are other pending tasks that are of higher importance and might interfere with the projects goals and if so what steps can be taken to avoid setbacks. Open and respectful communication can avoid a lot of project complications.