Undressed components keep 3 days separately, and hard-boiled eggs keep a week in the shell. Assembled and dressed it doesn't keep at all — the avocado browns and the leaves wilt within an hour.
The specific combination — chicken, bacon, egg, avocado, tomato and blue cheese on lettuce, arranged in rows. It was invented at the Brown Derby in Hollywood in the 1930s.
7 minutes for jammy, 9–10 for fully set. Cobb traditionally uses hard-boiled, but 8 minutes is a good middle ground.
Toss it in lemon or lime juice and cut it last. Keeping the stone in helps marginally, but acid is what actually works.