1. 1Verify all three NHTSA recalls are closed against the VIN at nhtsa.gov: fuel-tank corrosion (20V-231), brake banjo bolt (21V-561), and brake-line routing (25V-216) — the 25V-216 campaign record explicitly lists the 720S Spider.
2. 2Exercise the retractable hardtop through a full open/close cycle and check for water ingress, seal condition and correct operation — it is the Spider's one major addition over the coupé.
3. 3As with the coupé, insist on evidence of battery-tender use in storage, pressure-test the cooling system for the slow leak-free coolant loss owners report, and treat any 'damping failure' / Proactive Chassis Control warning as a real diagnostic item — the PCC II hydraulic accumulators are reported to weaken on earlier cars.
4. 4Budget for a specialist. McLaren service (every 12 months / 10,000 miles) commonly runs ~$2,000–$3,000, with larger multi-year services reported as high as ~$7,500–9,000.

• 20V2310002019–2020
  NVH foam pad under the fuel tank can trap moisture and corrode it, risking a fuel leak and fire; dealers remove the pad and inspect/replace the tank.
• 21V5610002019–2020
  Brake banjo bolt may be missing its drilled fluid-feed holes, disabling braking at one corner; dealers inspect and replace the bolt.
• 25V2160002020–2025
  Brake lines may be routed so braking activates on the wrong side, risking a rear-wheel lock-up; dealers inspect and correct the routing. The campaign record explicitly lists the 720S Spider.

US NHTSA campaigns for this model. A listed campaign may not apply to a particular car, and may already have been remedied — check a specific car by VIN at nhtsa.gov/recalls.