What the two halves actually do
There are two separate pieces of work here and they answer different questions.
The property assessment maps a building across sixteen directional zones of 22.5 degrees each, reads the main entrance, and reads the function of each room against the zone it occupies. This can be done from a floor plan and an orientation. It produces an accurate inventory of what is there.
The chart reading decides which items in that inventory matter, and in what order, for the people who actually live in the building.
The first without the second gives you a list. The second is what turns a list into advice.
Why a list is not advice
Map any real property across sixteen zones and findings appear. Every house has them. The number is rarely the useful information.
What a homeowner needs to know is which two or three to act on, because nobody acts on twenty. Handed an undifferentiated list, most people do one of two things: nothing, because it is overwhelming, or they act on whichever item was described most alarmingly, which is a poor basis for a decision and an excellent basis for being sold something.
Prioritising requires knowing who lives there, because which zones carry weight depends on which planets are prominent in their charts. Why can the same house be good for one person but not another sets out that mechanism in detail.
What the charts change, concretely
Three things, and they are specific enough to test.
The order. The same twenty findings come back ranked differently for different occupants. A finding in a zone that matters intensely to one person's working life is a footnote for someone whose chart runs elsewhere.
The attribution. In a household, findings get attached to people rather than to the building in the abstract. This zone matters for your work, this one for your partner's sleep, this one for the child's study. Families make decisions about rooms, and attribution is what makes a report actionable at that level.
What is safely ignored. This is the underrated one. A ranked report tells you what not to bother with, which saves more money than the recommendations cost. A generic assessment can never say this, because it does not know enough to rule anything out.
The honest test of whether it is real
You are entitled to be sceptical about whether birth details genuinely change a report or are collected because they sound impressive. The test is simple.
Would the recommendations have been different without them?
If a consultant takes your birth details and returns the same findings in the same order that any generic assessment of that floor plan would have produced, the charts were decoration. If the report reorders, attributes findings to individuals, and explicitly rules some things out as not significant for you, they were used.
Ask directly which findings were deprioritised because of the charts. A real answer exists. A vague one tells you what you need to know.
When a floor plan alone is enough
It is worth being straight that the chart layer is not always necessary.
If you are comparing several properties quickly and want to know whether any has an obvious problem, a plan-only assessment is proportionate. If you are doing a light refresh and simply want to avoid an obvious error, likewise. If the property is a short-term rental you will leave within a year, the ranking matters less because you will only act on one or two things anyway.
Where the chart layer earns its place is when a decision is significant: a purchase, a long tenancy, a property where someone will work every day for years, or a household that has been struggling and wants to know whether the building is a contributing factor at all.
When the house is not the problem
Sometimes the honest finding is that the property is fine.
That answer disappoints people who arrived hoping for an explanation, and it is worth more than a manufactured one. Where a household has real difficulty and the building does not account for it, the difficulty is elsewhere, and saying so is the correct professional response rather than a failure to find something.
Distinguishing those two is its own question, and kundli vs Vastu: which one is actually causing the problem addresses it directly.
What to bring
A floor plan if you have one, and an accurate compass orientation, which matters more than people expect and is the most common source of error in a self-assessment.
Birth details for everyone living in the property, as accurate as you can get them. Where a time is genuinely unknown, say so rather than guessing. Why birth time accuracy matters explains what a guess costs, and here it costs a confident ranking of the wrong things.
And the actual problem you are trying to solve. An assessment aimed at a specific difficulty is far more useful than a general survey, and it is also easier to check afterwards.
An Astro Vastu consultation takes all three. If you cannot supply a floor plan, that is workable too, and what a Vastu audit involves describes what the process looks like from the client's side.