1. Last-Minute Requests: Nurses may need to take unexpected time off due to illness or emergencies, which can disrupt the schedule. 2. High Demand Periods: During holidays or popular vacation periods, multiple nurses may request time off simultaneously, leading to potential staffing shortages. 3. Ensuring Fairness: Balancing PTO requests fairly among staff can be challenging, especially in larger teams. 4. Compliance with Labor Laws: Ensuring that PTO policies comply with labor laws and union agreements is essential.