I am flying from my home at 300 meters above sea level to Miami, at sea level. 9 hours later, I fly to Quito at 2800 meters. I've never had any difficulty with altitude before, but have only been near this elevation once. In Quito, there is a lift called the Teleferico, which takes you somewhere between 4000 and 4200 meters in 10 minutes, where you can hike to 4700 meters overlooking the city.
My thinking is the Teleferico is perfect to find out if I am acclimated enough to start mountain climbing. If I feel good on top of the Teleferico, I can set off for the 5126 meter altitude of Illiniza Norte or any lower mountain. If I feel bad, it is just 10 minutes back down to Quito plus time waiting in line.
My question is when should I attempt the Teleferico? Obviously, I won't try if I feel at all short of breath or sick in Quito, but what if I feel good when I land?