My 6 and 8 year olds have been dry during the day from just after their 4th birthdays. Neither of them had shown any signs of being dry at night. A couple of months ago FIL decided without telling me and DH first to offer them a series of rewards (lego) for being dry for a week, a month and a year. I was sceptical, and worried about it becoming competitive but the boys seemed keen so we gave it a go.
DS2 did really well, after one accident the first night he got his little lego model for being dry for a week. After 2 weeks he wanted to ditch the pull ups, all fine. He was a few nights off being dry for a month, then tonight he wet the bed. He woke up and started screaming hysterically and no amount of reassurance that it was fine and we were really proud of him for getting this far helped. In the end I had to get DH to get him out of the wet pj's and into the shower because I couldn't physically move him and he was rooted to the spot.
Meanwhile DS1 hasn't had a dry night at all and is still wearing pull ups. I'm worried we've put too much pressure on DS2 to be dry and I'm also wondering if we should be doing more to help DS1.