Sergio's home is so lovely, I recommend in whole-heartedly. As everyone else has pointed out, yes there are five flights of narrows stairs to climb, but it was so worth the climb to stay in this lovely oasis above Milan. You forget about the stairs as soon as you enter the home. We even had two suitcases to haul upstairs and we were fine!
The terrace is such a wonderful place to relax at the end of the day, and the apartment is thoughtfully appointed, and feels like a real home. if you want to cook- choose this place, as the kitchen was amazing! And if you don't want to cook, also choose this place, as we were only steps from many lovely restaurants, cafes etc. We did get a bit of street noise, but it didn't disturb our sleep and I believe that is because we were in town at the same time as the Alpini Assembly, which meant lots of extra people out and about. This home was about 10 mins walk from the Duomo, but we recommend walking the other direction as the street leading south to the navigli area has countless vintage shops and cool boutiques.