The interior design decisions that determine whether a high-end residential project succeeds or fails are made before a single tile is laid. Eight times out of ten, when a client returns mid-build to upgrade a spec they previously approved, the change costs 20 to 30 percent more than it would have at the start, because something has to be chopped out, redone, or re-coordinated across trades that have already moved on. That figure is what disciplined early-stage thinking actually buys.
The short answer to which decisions need to be made first, and which can wait: anything that affects the first fix needs to be locked early, even if the aesthetic conversation isn’t ready. As Nicole puts it, “the things that need to be considered are things that affect first fix”: the audio-visual brief, conduit routes, lighting points, whether the system runs on phase dimming or Dali. The look of the pendant can be finalised later. Where its junction box sits in the slab cannot. “The client doesn’t want to finalise the look right now,” Nicole explains, “but we need the point.”
“Eight times out of ten, when a client returns mid-build to upgrade a spec they previously approved, the change costs 20 to 30% more than it would have at the start.”
The interior design decisions that cost the most when left late
The decisions that quietly do the most damage are not the visible ones. They are the technical decisions that have to be coordinated with the first fix: where the AV consultant places speakers, which lighting protocol the electrician wires for, how the conduit is routed back to the central point. These are not aesthetic conversations. They are infrastructure conversations, and they have to happen before the trades arrive. When they slip, the project either pauses while specifications are pulled together under pressure, or it proceeds on assumptions that have to be unwound later. Neither outcome is cheap.
How TERRA structures the early interior design process
Most clients arrive at an interior project believing it begins with a mood board. The studio’s experience is closer to the opposite. The project begins with a brief, and the brief is where outcomes are quietly won or lost. TERRA’s interior design process is structured in stages for this reason. “Stage one is specifically about project inception and the client brief,” Nicole explains. “We do not like to go too far in stage one. We need to understand the client and what they basically need in their home.” The studio resists the pressure to move past it quickly, because the cost of an incomplete stage 1 is paid in stage 2, when the design begins to take shape on a back foot and every subsequent decision inherits the gap.
The interior design mistakes to avoid before construction begins
The most common interior design mistake to avoid is also the easiest to make: holding back a preference at the start because the client wants the studio to propose freely, to see what we can come up with. Then, after the designs are approved and the studio is deep into specification, the preference surfaces: by the way, this is what I actually wanted. The tangent has to be unwound. The schedule slips. The cost climbs. The client could have shared that detail in the first meeting and spared the project six weeks. The reluctance to over-specify the brief is well-intentioned, but it almost always costs more than it saves.
What to expect from an interior designer in stage one
The decisions that are genuinely irreversible, or close enough that reversing them eats the budget, are the ones tied to the building’s bones. Scarlett is direct on this: “If there’s a will, there’s a way. We can always change it. But joinery, you don’t really want to change things at a later stage.” Once a wall of cabinetry is fabricated and installed, changing its layout means tearing it out. Spatial planning sits in the same category. As Nicole describes it, “all of the thought that goes into considering location, positioning, how you’re going to use a space, if a client ends up changing that, everything is influenced.” Every electrical point, every plumbing run, every dog-tail off the main drainage line is positioned according to how a room will be used. Move the kitchen island a metre and the consequences cascade through the slab. What to expect from an interior designer at this stage is not concepts. It is questions, the right ones, asked in the right order.
Why materiality decisions compound over time
The trade-off clients underestimate most often is on materiality. At sample stage, presented with two options, one premium and one a cheaper alternative, clients tend to optimise for the quote in front of them. As Scarlett describes it, “clients end up changing elements on site once it’s installed because they don’t like how it looks or how it functions.” The upgrade now costs the original delta plus the cost of removal, the cost of reinstalling, and the cost of disrupting trades who have moved on to the next phase. Approving a sample is not just an aesthetic choice. It is a long-range commitment to how a surface will age, how it will perform under daily use, and how it will sit alongside every other material choice in the room.
Suppliers feel this too. “We work with such a range of amazing suppliers,” Nicole notes. “When we’re constantly changing things, specifically during the tender phase, it gets very, very frustrating. It makes it very difficult for our suppliers and also for us, and that’s where errors also happen.” The studio works with a network of fabricators and specialists who price tender packs based on a stable specification. When the spec keeps moving during tender, errors compound and trust erodes. None of it is theoretical. It is the daily texture of running a project that started with an under-specified brief.
The wider interior design market is full of studios willing to enter stage 2 with a half-formed stage 1, because clients reward speed in the early conversations and resist what feels like over-questioning. The trade press tends to celebrate the visual outcome and skip the discipline that produced it. None of this changes the structural truth: the project’s economic and aesthetic ceiling is set in the first six weeks, before any installer arrives on site. A studio that protects that early phase is choosing a slower, less photogenic approach to the work, and saving the client money they will not realise they were spending until the change orders arrive.
What clients are really paying for in the early phase
The honest framing is this: the fee paid for the initial design phase is, in part, the fee for stopping the client from making decisions they will regret. The studio is being engaged to ask the questions the client has not yet thought to ask. Who is the AV consultant? Where do you actually entertain? Where is the dog going to sleep? Will the joinery in this kitchen need to accommodate a second oven in five years? Is this marble going to look the same after a decade of dinner parties? These questions are not stalling tactics. They are the work.
“The fee paid for the initial design phase is, in part, the fee for stopping the client from making decisions they will regret.”
There is a longer pattern under all of this. Studios that resist the pressure to move quickly through stage 1 produce projects that age well, and projects that age well become referrals, become magazine features, become the thing that brings the next client through the door. Studios that capitulate to the speed pressure produce projects that look right on handover day and start unravelling at month six. The interior design decisions that shape everything are not the dramatic ones. They are the ones made calmly, in a room with a brief on the table, before anyone has talked about colour.
That is the discipline. It is not a trend. It is the reason some interiors hold their value, in every sense of the word, ten years later.
FAQ
What decisions do I need to make first when starting an interior design project?
Anything that affects first fix: the audio-visual brief, lighting layout and dimming protocol, joinery positions, and spatial planning that determines where electrical points and drainage runs go. The aesthetic finish on each of these elements can be locked later.
What is the most common interior design mistake to avoid?
Approving a cheaper material spec at sample stage to save money, then changing the spec after install. The change typically costs 20 to 30% more than choosing the right material initially.
How long should the briefing phase of an interior design project take?
Long enough that stage 2 doesn’t start on a back foot. TERRA’s studio leads resist shortening this phase. The cost of an incomplete brief compounds through every subsequent stage of the project.
What should I expect from an interior designer in the first meeting?
Questions, not concepts. A studio working at this level is using the first conversation to understand how the space will actually be lived in, who the technical collaborators are, and what the client cares about that they haven’t said out loud yet.
