Representative result from simulations runs. Each row consists of the result from 100 simulation runs under the same parameter settings and initial conditions. Left column: The median prevalence of gonorrhoea (fine lines) and chlamydia (solid lines) over 60 years. Right column: The average percentage of population away from home over the 60 year period, (males black and females white columns) and age range. First row: Individuals could stay away from home from 14 to 21 days per travel session, but partner seeking behaviour will not change while they are away. Second row: Same as first row, but there is 20% chance an individual who has a regular partner and cannot form concurrent partnership will seek a new partner while away from home. Third row: Same as second row, but only 20% of the population were allowed to move away from home. Fourth row: Same as second row, but individuals could stay away from home from 14 to 28 days per travel session.