<p>How many internships or REUs do you usually apply for? </p>
<p>When is the best time to apply for an internship or REU?</p>
<p>The upper limit on REU applications is usually determined by the number of recommendations that you can get without putting too big a burden on your professors.</p>
<p>The best time to apply for an REU is at least a month before the deadline. A lot of REUs have deadlines of late January to Early February. Some have them mid-January. Some have them later. The latest that I’ve seen is early May.</p>
<p>Ideally you’ll ask professors for LORs at least two weeks before the deadline when they aren’t really busy with other things (like correcting finals and papers). You will want recommendations from professors that know you well and have a good impression of you so this may limit the number of professors available for LORs.</p>