Keep him rear facing as long as you can :) 15 months is just the minimum. Which seat do you have, and how heavy/tall is he roughly?
I have a 15 month old too and my aim is at least 3. If we have another baby who will need the seat before he's completely out of it but he's over 3 I'll probably get him a forward facing one. If DC3 needs the 360 seat when DC2 is not yet 3, I'll get him another rear facing one, probably up to 25kg. DH will probably think I've gone mad :o but I don't really care.
If no other child needs the seat before DC2 grows out of it I'll probably continue to use it rear facing until he's too big for the seat, unless he complains about it. But among kids who are old enough to express a preference, a lot of them say they prefer rear facing because it's nice to have somewhere to rest your legs, rather than having them dangling. The only time children prefer forward facing, if they've been ERF to an older age
DC1 was forward facing from 18 months because I had no other option at the time, but I would have liked to have rear faced him to 2. That was 10 years ago, so you can see I've increased my aim :o
Generally the info you need to know about RF:
- FF seats reduce injury by around 60%, which when compared with no car seats/the vehicle seat belt - is fantastic.
- However, RF seats reduce injury by around 90% - which is much, much better. If you have the choice to RF, you absolutely should. This is true for every age group, and extremely well documented, as well as being basic physics, to spread the force of the impact over a larger area (the seat shell/whole spine, rather than a very small section of the spine in the neck, as a forward facing seat does). It's why the crew seats on aeroplanes face the rear, it's why astronauts face rear for rocket launches and landings.
- When you look at passenger death/injury stats across Europe taken from a time when most people turned their babies forward at about 8-9 months, there is a spike in deaths among babies of around a year old. This is because younger babies are rear facing so are protected better, and older children are not at quite as much risk from forward facing. This is a huge part of why the law now makes it illegal to turn babies forward facing before 15 months as an absolute minimum.
- However this is still part of a harm reduction strategy; you just prevent the largest number of deaths by setting the age here, it doesn't reduce them to the lowest number they could be. Supposedly, car seat manufacturers lobbied for the age to be set as low as possible, as forward facing seats are cheaper to produce (I don't know if this is true).
- In Sweden, where the national recommendation is to rear face until at least age 4-5, around 88% of one year olds and 82% of two year olds are still rear facing, most people turn their children forward facing between their third and fourth birthday with the most common ages to turn being around 3y3m and 3y9m. Sweden has the best record for child passenger fatalities in the world. Young children very rarely die in car accidents in Sweden unless the car accident is so severe that no car seat could have helped them survive.
- Everyone can rear face for longer :) The simplest way to maximise rear facing time is to use your infant carrier until it is totally outgrown, which is later than most people think. You can use it until either the weight limit is reached, the baby's head pokes out the top or the standing height limit is reached if it's an i-size seat. You can often use a baby seat until around 18m-2y.
- Of course, you may prefer to move to a larger seat designed for older children. If you purchase a rear-facing seat for use after the infant carrier you don't need to max out the baby seat, unless you want to. You should only do that if you're moving to a forward facing seat. For stage 2, you can get seats which rear face to 13kg/87cm, which won't get you any more weight than an infant carrier but might gain you some time height wise and happiness/comfort wise - likely until they outgrow age 18-24 months in clothing; to 18kg/105cm, which will get you until your child is about growing out of age 3-4 clothing; or to 25kg, which last children about until they outgrow age 6-7 clothing. Clothing size is a very rough metric, but should give you an idea - as parents often know how quickly their children move through clothing sizes and how early/late they move up to the next age band.
- The cheapest ERF seat is the Joie Tilt which can rear face up to 18kg and costs £70 RRP but is often reduced to £60-65 - I saw it at £50 this Black Friday. So ERF doesn't have to be out of reach financially.