As I saw the wicket-keeper fetching a fielding helmet from its hidey-hole, I just knew the news was going to be bad. In which of the following positions would I expect to need to wear a fielding helmet?

Fielding helmets are required for close-in 'silly' positions where the fielder stands very close to the batsman and faces high risk from hard-hit shots. Silly mid-off is a close-in position on the off side. Sweeper, deep cover point, and long on are all deep/boundary positions where the ball has less speed and the fielder is safer.