If you are looking for the absolute lowest price, research generally suggests that booking the day of your stay can yield the highest discounts—sometimes up to 15-20% off—as hotels scramble to fill empty rooms that would otherwise generate zero revenue. Apps like "HotelTonight" thrive on this last-minute inventory. However, "better" is subjective; if you book the day before, you have a much wider selection of room types and properties to choose from. By the afternoon of your stay, the most desirable (or the most affordable) hotels in a city may already be sold out, leaving you with only the most expensive or less-desirable options. Furthermore, "day-of" booking is a risky strategy during holidays, festivals, or major sporting events when city-wide sell-outs are common. For a low-stress trip, booking at least 15 days in advance often provides the best balance of a fair price and guaranteed availability. Only rely on same-day booking if you are flexible with your location and don't mind staying in a "leftover" room.