Project stage and approvals
Nothing separates enquiries as cleanly as where the project actually is. Concept, design, tender, execution. Add approval status to that and you can see immediately whether work can start this quarter or whether the client is still waiting on a sanction that may take a year.
Drawings, BOQ and a measured site
These are the commitments. A client who sends drawings has paid a consultant. A client who issues a BOQ is running a comparison, which is good news if you are on the list. A client who lets you measure the site has shortlisted you, and that is when estimation effort starts being worth spending.
Funding and who is asking
Sanctioned money moves projects; intended money does not. And the person enquiring matters as much as the enquiry. An architect gathering budgetary numbers, an owner with sanction in hand, and a main contractor building a subcontract package are three different conversations with three different follow-up plans.