Yeah, it's common now and pretty much expected as part of their early childhood education. It really does benefit them to go - they do a lot of play-based learning that is semi-structured and early childhood educators now have a curriculum to follow that align with the curriculum that is used in schools. It's like a precursor to their formal education. Its all part of preparing your child for school (even though I know it seems a long way off now) as well as helping them with any difficulties they may have - by attending preschool any problems are picked up early and intervention can take place well before they start school. I know you say your little fella is pretty well socialised, but preschool is different in that it is only children of his age group. TBH, even if you don't send him now he's not going to miss out on anything in that one year, but the year before school is vital IMO, and I'm sure you know that already . I was of a similar view to you with my first - he only attended in the year prior to him starting school because we just didn't think it was necessary - he attended playgroup and had two younger siblings. It certainly didn't hold him back by only going one year and I don't regret doing it like that, but the rest of my kids have all attended from 3yrs old and done two years at preschool before starting school. I have only ever sent them for one day per week, but many will send them 2 days per week. However with DS2 being our last child he is now attending preschool 2 days per week for this last term - prior to that he was only going one day. But he needs it - he just doesn't get the stimulation at home during the day because he's the only one here.

Plus, this has nothing to do with the actual child attending preschool and the benefits they will get from going as a 3yo, but in some places you may find that the waiting lists are huge and preference is given to those who are already attending. This was the main reason why we sent our next 3 kids at 3yo - because there was a boom in the town which meant a lot of new, young families moved here and places were scarce as hens teeth. We were told that there would be an order of preference put in place to cope with the demand - so at the top of the list were children with special needs, then came children under DoCs/Foster care, children/families already in their system (having an older sibling already attend in the immediate year prior) and then everyone else. They had limited places and the waiting lists even for 3yo's were going to be huge so it forced our hand. If you live in an area of high demand then this may be a problem for you too. I would be calling all your local preschools and see if that may be the case for your area. It may not be what you really want to do, but you may have to if it guarantees him a place as a 4yo.