Weekday and weekend
Sathorn and Silom are busiest from Monday to Friday: banks, law firms, embassy compounds, office towers and street food at lunchtime on Silom Road. At weekends the business blocks go quiet, which some residents like and others find flat. Sukhumvit keeps going all week. The lower sois around Nana and Asok carry much of the city's nightlife and stay loud late, while Phrom Phong, further east, has Benchasiri Park and the Em District. Visit a shortlisted building at 6pm on a weekday and again on a Sunday morning.
Where the money goes
The Sathorn premium buys a shorter walk to the office and larger layouts in older buildings. It does not buy higher rent: serviced apartment rents are lower in Silom/Sathorn than in Sukhumvit. If the purchase is mainly an investment, that settles it for Sukhumvit, close to a station and in a well-run building. If you will live in the flat and work nearby, Sathorn earns its price. Test the numbers in the rental yield calculator.
Buying well in either
Both districts are heavily supplied, and Bangkok should stay a buyer's market for the next one to two years. The prices above are launch averages, so ask for recent transfers in the building, read the juristic accounts and check the sinking fund. Title deeds and due diligence lists the documents. If you want the park and have a larger budget, compare Lumpini and Ploenchit.
