I don't live in a new house myself, but I live in an area with "shrinkable clay soils".
One thing I worry about is trees.
The developer puts in a landscape scheme, and where there are trees planted, the builder has to put in deeper foundations to prevent any possible damage.
What isn't done, is assume that house buyers will plant their own trees. So the other houses where no trees are marked on the plans don't have deep foundations, so in future, when they plant trees, many years down the line they could in theory have problems.
I think that developers should be required to put in foundations deep enough to allow house buyers to plant trees without worry....but they won't, because it costs more.

I think often not enough care is carried out by builders when they reconstitute the soil around new builds, the soil can be polluted with liquids spilt in the construction process or can simply be so panned down sub soil wise that the new gardener has trouble.
I do take issue with dampflippers comment about trees. There is so much paranoia about trees in gardens and foundations. My neighbour has a massive flowering cherry growing on the boarder between our properties planted years ago by the council. Its literally about 5ft from their main wall- is the house falling down? no it isnt.
A gardener acting with care with tree selection should have nothing to worry about when gardening in a modern home garden.

"I do take issue with dampflippers comment about trees. There is so much paranoia about trees in gardens and foundations. My neighbour has a massive flowering cherry growing on the boarder between our properties planted years ago by the council. Its literally about 5ft from their main wall- is the house falling down? no it isnt"

But do they have shrinkable clay? And how deep are the foundations?

I'm also in a region with shrinkable clay, and have dealt with the subject of root-induced subsidence professionally. It is not just something to consider 'paranoia'; there is an extensive body of scientific literature and legislation on the topic.

Resin

Just a note: not all clay soils are shrinkable clay. I happen to live an an area where it is present, and have seen the effects.
My point of view is that if you are building in such an area, then the foundation design should be required to be sufficient to cope with a medium or small sized tree to be planted in the garden. It should be assumed that residents WILL plant a tree, and not that the builder should be able to get away with the cheap option and that the resident would have no idea that they should therefore NOT plant trees.

Its widely recognised that to many trees are removed across Britain due to concerns about damage to property, often there is no issue but the owner of the tree removes it incase they get sued by a neighbour etc at a later date which has a huge impact on our environment.
If "shrinkable clay" is such an issue across the UK modern homes should be built with suitable foundations but lets face it they still let builders build on flood plains so what hope do we have.
May I point out in my previous post I stated "A gardener acting with care with tree selection should have nothing to worry about when gardening in a modern home garden."
Thats the important point- acting with care on tree selection. The average new build does not have a garden large enough for a "big tree" your not likely to plant a Sycamore or a weeping willow in your new postage stamp garden hence the average small garden tree should not pose a problem.

My experience of builders was when we had some terraced beds built a few years ago, while my back was turned they dumped the worst soil they could find in to fill them! It varied from the very good (what used to be the lawn) to stuff you could literally make pots with, bright orange clay.