Considering only the main, present-day events of the first season of Daredevil, how much time passes from the beginning of episode one through the end of episode thirteen?
I've been wondering this as well, but have been unable to find an official answer anywhere. I've come to a conclusion based on guesswork, but obviously it involves speculation:
From the first time Daredevil dons his black suit on-screen to the debut of the red suit, it appears that approximately one month of time passes in-universe.
Now, here's my reasoning. The first several episodes appear to be happening back-to-back, with each episode connecting almost seamlessly, with only a few hours or less passing between episodes. There are a couple of cases where he gets injured pretty badly, and afterwards disappears for a day or two - likely spending the time resting and meditating to
accelerate his healing process, as mentioned by Stick.
By Episode 9 "Speak of the Devil", we can assume that roughly two weeks has passed so far, when Daredevil is
severely injured - almost killed - during his fight with Nobu.
After this event, he disappears into seclusion for several days, possibly a week or more. Following that, we have to allow for several hours, or even days, in order that
Melvin can design and create the red suit.
Therefore, with a minimum of healing time in-between bouts, we're looking at least a month from start to finish, obviously not including any of the time shown in flashbacks.
UPDATE: I went back to the first & last episodes and tried to get dates off of the newspaper articles ("Union Allied Scandal" in pilot & "Daredevil Collars Fisk" in finale), but the dates on the newspaper are illegible, even in the closeups. Perhaps someone with a higher def screen or viewer can provide those.