The answer isn’t very clear and I can only give you advise. Control freaks will lean towards booking every detail in advance and planning every minute of the trip. This is a stressful way to make sure you see everything you wanted to see. The downside is you have no freedom to make changes. Your itinerary is set. There is nothing worse than booking that gondola ride on the grand canal and when the day arrives it’s pouring rain. Or booking a food tour and waking up feeling sick. On the other hand, arriving clueless and unprepared can ruin a trip. For example if you want to see the Anne Frank House in Amsterdam you had better book it in advance. The tours are limited to a certain number per day and depending the season they book up as much as 3-5 months ahead of time. Peak season spots go fast and if the tour is the main reason you’re going to Amsterdam you may want to check availability before booking a flight. The decision as to when to book also depends a lot on how you like to travel. Greece during peak season will be super crowded and that quaint waterside B&B you want to stay at will probably be booked up. But if you don’t mind going during the shoulder season you can probably get away with not booking 3 months out and you can save yourself some money as well. Most seasoned travelers I have met lean towards leaving plans lose but all agree you should research your destination before arriving. Some tours are more like traps. If your in Cebu and looking to swim with whale sharks you might be tempted to book your tour before you leave home. But no matter how early you book you are still waiting in line when you get there. All the tour operators do is get you there. They tell you they know where the sharks are and offer to pick you up at your hotel and bring you to the sharks. Once you get there you are handed over to the park operators like anyone who might just walk up. The truth is you can arrange your own private taxi driver to take you there, wait and bring you home as well as stop wherever you want along the way for a fraction of the tour price. We avoided the loud, crowded $340 ($170pp) tour bus and hired a private taxi for the day for $80 and got to stop at a waterfall we had heard about and a lunch stop of our choice. Another advantage was we had a three day window so we were able to go on the morning that the weather was the best instead of booking 2 months out and hoping for a sunny day.
This works great on Asia. In Borocay we could have booked an island tour for $30 per person (3 of us) but instead we waited until the weather was in our favor and hired a local with a tuk tuk for $40 to show us around. We not only saw all the highlights but we saw many spots a tour wouldn’t have brought us to like a private beach protected from tourists that had unique shells used for jewelry and we saw it all at our pace. The local knew just where to view the sunrise at the highest point on the island that was closed to the public and even had a friend with a boat that we ended hiring for an afternoon of island hopping and snorkeling at about a fifth of what a crowded tour what have cost. He even cooked us a massive feast of local delights while we explored the island.
Another great example is Japan. Had we not done our homework we would not have known that tourist can’t buy a rail pass while in Japan. You must order it in advance from another country. Getting around buying individual train rides will cost you a fortune whereas the pass lets you ride unlimited local and bullet trains.
The best advice I can give you is do your homework and relax. Don’t let FOMO (fear of missing out) dictate your trip. You’ll never see everything and I have learned that the more you like a place the deeper you will want to explore it. Book in advance when you have to and leave the rest of the trip open. The more you just let things happen the more authentic your experience will be. That little food joint the locals tell you to try will be better than anything you can book on the Internet. Let the travel bug guide you and trust in the travel gods! It’s worked for me.
