When seeking letters of recommendation during undergraduate studies, it's important to build strong relationships with professors before making requests. Ideally, students should approach professors in their third year, showcasing their knowledge and passion for the subject. Recommendations are most valuable from those who know the student well, particularly in relevant contexts like research or teaching. For students applying to programs like REUs, it's advisable to ask professors for recommendations, even if the relationship is limited. Utilizing university reference services can streamline the process, allowing professors to submit letters directly to multiple applications. However, personalized letters tailored to specific applications are generally preferred. To facilitate this, students should provide professors with a packet that includes details about the application, their CV, and any necessary mailing information, giving them ample time to prepare the letters. Professors may be willing to write multiple letters, but it's essential to gauge their capacity and willingness to do so.