Get a long lasting infant carrier, like Britax Babysafe Core, or Cybex Cloud G, which can be fitted with seatbelt. The newer Britax seats including this one fit onto all the prams which use Maxi Cosi or multi-brand type (universal) car seat adapters. (So do Cybex). The Britax is cheaper whereas the Cybex is possibly more comfy if you're likely to use it as the seat on your pram, which I found quite handy to be able to do as a non driver if I was getting a lift somewhere.
In general, ignore the age ranges that are given by the manufacturer - they are not very helpful. There are two things which will tell you how long the seat will last:
- The height limit - and it doesn't matter exactly what it is, but only if it's over or under 80cm. A height limit under 80cm (most commonly 75cm) is usually reached before a year of age. If you're likely to have a very long baby because they are measuring big and/or both parents are tall, then you might be unlucky and reach 75cm before 9 months. Over 80cm usually gets you to over a year and then their growth slows down so much that 83/85/87cm doesn't really make a difference as they will outgrow the seat physically first. Weight limits tend to be 12/13kg anyway which is massive. Babies rarely ever outgrow an infant seat by weight.
- The physical size of the seat - babies outgrow a car seat either when their head starts to stick out of the top of it (doesn't matter about legs) or if it has a headrest which moves, when their shoulders don't fit under this any more. They also can't go more than 2cm past the top harness position. It's OK for their shoulders to be less than 2cm higher in rear facing seats though.
The Nuna and Joie seats with the isofix built into the seat aren't much use to you, because they have a 75cm height limit which is usually reached before a year old. It's a shame because I think the idea is good, though not really necessary given you can fit most infant carriers using the car seatbelt anyway!
If you want to, you could go into a shop and compare the length of the backrests of different seats to find out which is the largest - take your own tape measure. To adjust the headrests, there is often a little squeeze button/lever type thing at the top of the headrest. Or sometimes you open a compartment on the back of the seat to move the straps and headrest up and down.
It is quite rare to have an infant carrier seat actually last until age 2, although I would argue it's definitely possible. Most people switch around age 1 because their child wants to sit up more and won't be contained in a reclined seat like this. But I have definitely known people, esp without their own car, use these seats for longer and it can be done, as long as you get one with sufficient capacity.