I had 300ft originally. After some thought, I cut it into a 100 ft length and four 50 ft lengths.

However, in real life, most of my problems (tying stuff down, etc) lent themselves to shorter lengths. So now I EDC a 10 ft piece with a 20 ft length in my bag. Tightly wound, the first makes a good key fob and the second is barely noticable among my school supplies, yet the two have proved highly useful. For hiking, my car kit, or trips, a 50 length would be appropriate, but a ten and a twenty are fine for daily urban life.