The rate you saw,
secured or spent

Point 1Locks: buying certainty by the day

The mechanism: a rate lock fixes your quoted rate for a window — 30, 45, 60 days standard, longer bought at premiums — against the market's movement while the closing chapters' machinery grinds. Unlocked, you float: the closing-day rate is whatever the market says, for better and worse.

The NYC-specific stress: closing timelines here strain standard windows (the timeline chapter's co-op tracks especially), making lock-length selection a real decision — the 60-day lock's small premium against the extension fees a blown 30-day window incurs. Extensions price per-day or per-week once windows lapse; the lock chosen to the realistic closing date, plus buffer, is the discipline.

Point 2Points: prepaying the rate down

The trade: discount points — one percent of loan each — buy rate reductions (commonly around a quarter-point of rate per point, varying with the curve), converting upfront cash into monthly savings. The break-even arithmetic decides: point cost divided by monthly saving equals the months to recoup — hold longer than the break-even and points profit; refinance or sell sooner and they were donations.

The refinance overlay sharpens it: points paid then rates fall invites the refinance that strands them — the cycles chapter's rate windows arguing against heavy points in falling-rate expectations, for them when rates seem floored and holds run long. Foreign-national program points price the same math at their own levels; the tax treatment (points' deductibility rules on rentals versus residences) adds the preparer's line to large decisions.

Point 3Credits: the reverse gear

The float-down deserves its ask: some lenders re-price locked rates once if the market falls meaningfully before closing — a free option where offered, a cheap add where priced. The volatile-rate seasons that strand locked borrowers watching rates fall are exactly when the clause earns its request.

Point 4The decision frame

The selections, sequenced: lock length to the realistic timeline plus buffer (the extension fees teach expensive lessons), points by the break-even against honest hold expectations (the exit chapters' horizons consulted), credits where cash at closing binds or holds run short, and the float-down requested wherever volatility looms. The comparison discipline throughout: lenders' offers compared same-day and same-structure — rate-and-points combinations only comparable when aligned.

The cross-border addendum: foreign-national programs price all mechanics at their own levels (the mortgage chapters' premium context), relationship pricing at international banks rewards the banking chapters' architecture, and the rate conversation belongs in the financing sequence early — the credentials chapter's pre-approvals carrying lock options the bidding week has no time to negotiate. The fine print, read once, prices every future loan.