Izumi's apartment was perfect for a month-long stay. It's spacious and very comfortable for three adults. The living room is a great option for WFH, and I was even able to teach online yoga since the furniture is easy to move. The kitchen is narrow but is still functional enough for preparing homemade meals that can be enjoyed at the large table on the terrace. The location is convenient, with easy foot access throughout old-town Sintra, including a great bakery (Padaria Saloia), health food store with vegan menu (Ekvilibro), and the local farmers market (only some vendors have organic produce so be sure to ask before purchasing).
The only downside to the location is street noise during the day, particularly on weekends - the town is overrun by motorized tuk-tuks, which are the worst offenders, though I did spot a couple of electric ones. To access the building entrance on foot, one must either walk up several narrow cobble stone steps, if coming from the old town, or go up a hill. This is the case for most of Sintra, as it is an old town with narrow streets, so keep that in mind when selecting your luggage!
Finally, Izumi is a wonderful host, extremely generous and very accommodating.