Have walked it a few times, 45mins to an hour is about right, had a knee replacement last year, so couldn't walk it, but booked a taxi with Olga, at Olga Travel, took us up at night, had a nice meal, and she picked us up later, much later! cost 20 euros, between four of us I reckon its worth it.
As everyone says, if you do walk it, set off early morning, 9ish, before it gets to hot, and take plenty of water! we will be going up in two weeks time when we arrive for eleven days of heaven! again!