The first usually happens before they're even born, when nesting sets in big time and you and/or your partner are busy applying wall decals, buying cot sheets in a matching shade and generally making your baby's room everything you ever dreamed it would be.

As they grow, so too does the number of stuffed toys, books and gifts they accumulate at Christmas and birthday parties.

Before long they may be expressing themselves more independently, with posters on the wall and other markers which reveal their passions, be it music, sport, clothes shopping or gaming.

This is usually the messiest period, which spills into the tween years, when dirty dishes lurk underneath untucked bedsheets and the dreaded floordrobe takes on a life of its own.

One day however, your pride and joy will probably announce they want to make their room "less babyish", and not only is a cull in order, but also a plan to create a more mature space which reflects the person they are now.

We experienced this step recently and there are some definite takeaways you might find helpful for when this day arrives for you.

Let them take the lead

This point is so important to remember, especially if your bible is Architectural Digest or you're having deep nostalgia about what your ideal bedroom looked like when you were a teen.

Ultimately, this is their personal space and quite possibly the first time they've had an opportunity to express their maturing tastes and flex their version of a creative muscle.

If this means displaying all their favourite trainers on a shelf, or adorn the walls with newly discovered artwork, let them do it.

Create piles

Any effective approach to organisation requires some sort of pile-making, and this is one aspect where your help could really be appreciated.

The familiar toss/keep/sell/donate categories also apply to a bedroom overhaul, and encompass clothes, books, toys, games and the hoard of plastic knick-knacks they've quietly accrued.

The issue of nostalgia

The sorting stage can be a tough one, especially if either of you find it hard to let go of sentimental items. Suggest keeping just one favourite plush toy, or only the books given to them by a grandparent or other special person.

Some teens may be open to taking photos of favourite objects from years gone by and saving them in a digital album, so they can hold onto the memory and not the stuff (this can also help form lifelong clutter-clearing habits they'll thank you for one day).

Work to a budget

The very notion of a bedroom facelift means there will be some cost involved.

It may be a new bed, or some more age-appropriate bedding. Perhaps it's a new paint colour on the walls, or just some affordable frames for photos of their BFFs.

Identify what you're prepared to spend beforehand and have an open conversation with your teenager, so you're on the same page.