Every off-plan listing states a handover date. Treat it as an intention rather than a commitment, and ask what the contract says happens if it slips — a date with no consequence attached to it is not a date.
Payments are released against milestones. The value of that structure depends entirely on who signs off each milestone. An independent supervising engineer or quantity surveyor certifying progress is meaningful; the developer certifying their own progress is not.
Ask what happens to your money if construction stops. Staged payments held by a notary and released on certificate are a very different proposition from payments made directly into a project account.