I am wondering why do LEGO boxes have a maximum age limit printed on them?
My girlfriend has just gifted me LEGO Starfighter (8088) and it has an age range of 8-14. Why not just write 8+? Are there any technical objective reasons?
I believe it shows the target age range of the model - perhaps kids who've been doing all the harder Technic or more complex models - for example the VW Camper Van is rated 16+ - and might find it a bit "simplistic".
Other examples include The Super Star Destroyer, also at 16+, the Tantive IV and Republic Drop Ship at 14+, and the Death Star and others at 12+:
I have a memory - possibly false - of Lego boxes being labeled with ages like "8-99" in my childhood.
– Joe Wreschnig
That's correct. The Creator theme used to mark sets aged X to 99.
I think the LEGO marketing team were going along with the idea that you're never too old to play with Lego. The Creator product line produced brick buckets and tubs that became popular with people wanting to expand their collection or pick up from when they last played with LEGO as a child.
Todays brick buckets and tubs are marketed towards children aged 4+, which I'm sure would make LEGO hundred year old fan's happier.
The only age recommendation that should be taken seriously are the 3+ years choking hazard warnings on most LEGO sets. LEGO bricks in the Duplo or Quatro range may not have this warning as the parts are designed to be safe for younger childern.
Aside from that, the age range of a set should not be taken overly seriously but as a rough guide. A set with a higher age band tends to be a more complicated or challenging build.
It is an indication for the target audience for that set. It is mostly to guide people with little knowledge about child development toward a set. It's a rough guide, how much the child enjoys it is very much dependent on the child. But 10 year olds will be less likely to enjoy Duplo and be happier with Star Wars LEGO.
On the other hand, I really like building with Duplo especially with my nephew, or when my son is destroying my creations.
The complexity of the model and the expected time to complete it will increase with the recommended age.
Lower aged sets, like the Juniors line, feature builds that rely heavily on standard stacking and more basic bricks.
As the age recommendation goes up, you'll see more advanced building techniques such as offset stacking (think stair stacking), studs not on top (SNOT technique), thinner walls (think 1x4 instead of 2x4), more plates instead of just bricks, and more.
Sets for younger children are also designed for the type of play those ages engage in. And they tend to feature brighter, primary colors, which also appeal to those age groups.
Looking at set 10672, LEGO Juniors Batman: Defend the Batcave, we can see evidence of these things:
Now, we can contrast this with a slightly higher age range set, 75099 Rey's Speeder.
The Batman set was ages 4-7, and this Star Wars set is ages 7-12:
You won't necessarily be able to apply these attributes universally across sets, especially since the age-ranges sometimes overlap, as seen in 60043 Prisoner Transport, which has an age range of 5-12.
None of this is to say that younger kids can't assemble and enjoy older-ranged sets, but the ranges given are typically where the most enjoyment and least frustration will be found.
Something else you won't see on the box is the difference in styling of the building instructions. For the Batman set's (PDF), we see there's only a single task per page, and they're often broken down into smaller steps or have large, clear arrows indicating placement. In the Star Wars set's (PDF), we see that each page has two numbered tasks and placement is less likely to be indicated by arrow for simple tasks.
These differences in instructions are because of the expected abilities and attention spans of the intended audiences. Again, this is to reduce frustration and enable the children to be more successful building the sets without relying too heavily on the adults to help.
The LEGO company does a lot of research into what types of play are better for children at different ages, because it gives them a better product. You can seem some of the information they provide parents about types of play on their Parents website, and more involvement with child education from their LEGO Education company.
This answers comes from my experience as a consumer of LEGO product for different age ranges and as a previous customer service representative. I was asked questions about the recommended age ranges on a weekly basis, and the answer I provided to customers was similar to the answer here.