[nctomatoman]

Hi - just back from Philly business trip. You can pick eggplant any size you like - from egg sized to full sized (which of course depends upon the variety). Also, picking will induce more flowering/production, so maybe try some at different stages to see what suits you best. Once they stop getting larger and are at their full size, they will slowly turn yellow - at which time seed can be saved (but they are not good for eating at that stage).