Letters of Recommendation Not in By Deadline

[Dee2017]

I requested three letters of recommendation from my professors.  One got hers written right away but the other two have still not submitted anything and my first deadline is for January 1st.  Many of my friends who asked these professors for letters have the same problem.  When CSDCAS has an application deadline, does that mean it is the deadline for the applicant to submit her materials or that EVERYTHING must be submitted by that date?  

[NYslp93]

I believe there's a little bit of leeway in terms of when they can submit their letters, it's not due the same time as your application but there is definitely a timeframe where your entire application including materials need to be received.  I would definitely send a "friendly" reminder email or two.