The first feasibility study I signed off was wrong
I trained as a quantity surveyor and moved into feasibility work in Abu Dhabi in 2019. The first study I signed on my own was for a mixed-use plot. I built the entire revenue side from asking prices, because asking prices were what I could get quickly.
The client took it to a bank. The bank's analyst asked one question: how long do those units sit before they transact. I did not have that number. An asking price with no exposure time is a wish, not a forecast, and he said it politely, and everybody in the room understood anyway.
What I do now is slower. I take the same unit type, record the asking price on the day I see it, and check the same listing every two weeks until it disappears. After three or four months you have a distribution instead of one number. It is tedious, and it is the only part of my work I would defend in front of a bank.
I mention it here because most training material I see teaches the model and not where the inputs come from. The model is the easy half.
Also whoever designed the export in our cost software should be made to use it once.
Update to my own post, two people asked what I actually track. A sheet with three columns: date I saw the listing, asking price, date it disappears. For the Abu Dhabi and Dubai side I take them off https://emirates.estate/ and screenshot each entry, because a listing that vanishes without a screenshot proves nothing. Around forty entries a month. About a fifth come back later at a different price. That is also data.