For most visitors, one full day and one night is the ideal amount of time to spend in Old Phuket Town. The area is relatively compact, with the most famous Sino-Portuguese architecture concentrated along Thalang, Dibuk, and Phang Nga Roads. A few hours in the morning are perfect for exploring the colorful shophouses, street art, and small museums like the Thai Hua Museum before the midday heat becomes intense. In the afternoon, you can enjoy "café hopping" in the many boutique coffee shops or visit local shrines like the Jui Tui Shrine. However, the town truly comes alive in the evening. If your schedule allows, you should visit on a Sunday to experience the famous Lard Yai (Sunday Walking Street Market), which transforms Thalang Road into a bustling hub of street food, handicrafts, and live performances. Staying overnight allows you to enjoy the town's unique "boutique hotel" scene and see the buildings beautifully lit up at night without the rush of a day trip. If you are a dedicated foodie or photographer, you might extend your stay to two nights to try more local "Baba" (Peranakan) cuisine and capture the town in different lighting, but for most, 24 hours is the "sweet spot" for a complete experience.