My 2009 Jazz EX shift 1.4 has four plugs despite several people, including a garage, telling me that it had eight! I recently replaced my plugs with 4 Bosch Iridium plugs at 60,000-miles and it's running better than ever. Incidentally, it's possible to replace them without removing the front scuttle cover and wipers, but it's fiddly and you're working 'blind' and it took just a bit more than half an hour.
Sent from my SM-T585 using Tapatalk