Several weeks or months in advance, the offer is wide and rooms in the best hotels offering the best quality/price ratio will still be available. This advice is only valid if you want to know which hotel you will go to during your trip. In some countries it is possible not to book in advance and look locally for a hotel with a good quality/price ratio. This is what I did during my trip around the world. Whether in Asia or South America, it is easy to quickly find a hotel and have the opportunity to negotiate the price on the spot.