This path from the Montaña Blanca parking lot is by far the most popular and tourist-friendly way to reach the summit of Teide, coming at it from the east via Sendero 7. There are 3 main variants to reach the summit from the west, all eventually via the scrambly Sendero 9. They are more technical/steep/challenging than this one.
**NOTE** this FKT seems to have been created with reference to a specific Strava segment ( https://www.strava.com/segments/17681585 ), so i've submitted my completion time on that basis. If you are keen to pursue this FKT, be wary of the many similar/overlapping segments on the route.
Seeing the top of Teide is a perpetual dance of (1) trying to get a permit on a day you're visiting - be sure to book it months in advance if you're not with a tour group, (2) hoping Telesforo Bravo, the final trail to the summit, actually remains open, and (3) reaching the trailhead promptly enough to not miss your permit's 2-hour time slot.
My experience on the day:
The weather was finally good enough for the path to stay open, unlike the first 5 or so times i'd lined up a permit. I'd run the round trip of the lower trails once before, so the increasingly steep ascent from parking lot to summit wasn't a surprise. That said, the last 10-minute climb beyond the permit gate did take my breath away in all senses :-) Near the very top, there was some careful stepping to avoid the tiny fumaroles on the trail, and the sulfuric smell got pretty strong -- tried not to linger! Turned around and got on with it, a quick pic then back down to the parking lot. Note that the guards can stop you for a permit-check in *both* directions, when entering and exiting the gate to the final trail. Just one stop for me on this day.
Food/water - no help / external sources or public taps. Carried a waistbelt with 3 gels and 450ml of water, ate all the gels and got through most of the water.
When the weather is good, the climb won't necessarily be much faster as you'll have to spend energy going around the many tourists clustered near the top (just when you're extra tired), and there's always an unknown as to how long you'll be standing in line for permit-check.