The purchase agreement itself carries the real risk. Builder contracts often include occupancy extension clauses, an allowance system for finishes and a closing adjustment formula that a walkthrough alone will not reveal, and a lawyer should review that agreement, typically for $800 to $1,500, before a deposit changes hands.
A local agent also brings ground-level knowledge a national builder's sales office does not have: which lots sit on a collector road, which builder has a history of delayed occupancy dates, and how a specific new-build price compares to resale homes of similar size nearby. That comparison is the part an online-only opinion cannot make.
None of that shows up in a floor plan brochure, which is written to move that project's inventory rather than to protect a buyer's position. Get your hand-reviewed valuation from Joel Dyck.