I'm with grounded on this.
In 1st generation turbojet powered aircraft, you did not know how hot your tyres and therefore brakes to a certain extent, would be after a long taxi to t/o in high ambient temperatures at MTOW. If there was any doubt we used to leave the gear down, sometimes for up to 20 mins. Terrain permitting in a lot of cases of course. 250 kts of rushing air is as good as any fan that I know of. Yes we had wheel well fire detectors, but they don't detect a burning bogie being retracted into a wheel well.
Yes you could say it was guesswork but common sense did prevail in most cases.