I booked this apartment for 40 days but did not notice that the apartment is on the underground floor(which have their disadvantages). Also from the photo it seemed to me more spacious.
Thanks to Kaan, he agreed to move us to his other apartment one floor above where I happily live right now.
Overall Kaan is the great host. He will help you with every problem that you will face.
You'll have everything you need at the apartment(the iron, towels, washing machine+powder, сezve, all required dishes and so on). His assistant will also be asking you several times a week if you need anything while you stay.
The only thing is: I can not recommend this part of Sisli for everyone.
If this is your first time in Istanbul it is better to choose other areas.