Focal length anxiety
There's a huge recurring trend that goes viral on YouTube and social media, professionals and hobbyists claim that they don't need anything just one camera and one lens. If you do a little search you can find the polar opposite, you need every professional lens to get the perfect shots. Not so surprisingly the truth is somewhere between, however, the one camera one lens is a valid and excellent advice in many cases.
Focal length anxiety
So what is focal length anxiety? Simply, that is when you look like a moving camera shop with a huge backpack that contains all the lenses you might need. Even if you'd be fine with a 35 or 50mm, you have a 15-35mm, a 70-200mm, and a few primes. Just because what if. What if you find that the 85mm prime would suit one or two pictures better? What if you need that additional 100-400mm lens for some shots?
Of course most of the time this much lens choice is rather suffocating. On one hand, you carry around a ton of gear that is so heavy your whole travel will be essentially a workout. I think anyone will soon regret the whole idea of having all the lens choices available. On the other hand, it can be worse for photography. Why? Because you might end up thinking about the lens and changing the lens instead of actually photographing. Constantly switching lenses is not only uncomfortable it also means that you'll miss shots as you're occupied with changing to the perfect lens. Which might not be perfect as you try it so you might have to change the lens again. I know it sounds a bit funny but I saw many who follow this method. It is not fun. I was in this camp bringing all the possible choices with me. It takes out the fun of the travel.
©Leica
Decide what you need
Instead of being a moving camera shop, it is much better to decide what you need. Yes, you may miss a few shots that would've been better with a 200mm, but as soon as you limit your choices, your photographic eye and brain will adapt and you'll take many more great shots with what's available. The additional benefit will be that your whole gear is small and lightweight. In the end, you might even enjoy being present and taking photos.
If you travel for fun
When you're traveling for vacation or to explore something new, it is great to have only one camera with one lens. Believe it or not, your brain rapidly adapts to the so-called limitation of having only one focal length and you'll shoot amazing pictures. Probably much better ones compared to having a plethora of lenses in your backpack. And it's not about weight. It's about simplicity. With one lens we eliminate the whole thought process of choosing the right focal length. You start to think, see, and compose in that particular focal length and that is very liberating. The other obvious benefit is you're going to enjoy your stay. Instead of swapping and carrying around lots of lenses.
©Leica
If you're on a commission
This is different. You must have the perfect focal length for the job. At first, having much more gear than you'd ever need for the job is natural. But with time and experience, you can limit your choices to the really necessary ones. Your photo bag becomes easier to carry, and you have a limited choice of lenses, but those are the very best ones for that job. I would never recommend leaving essential gear at home. But still advise you to leave everything you won't need at home. With experience, you will know what you don't need. Of course, if you feel safe when you have a complete set of lenses no matter what the needs are, feel free to carry around your complete lens lineup.
What is the golden ratio?
With experience, I more and more become a lens minimalist. That doesn't mean I won't go with multiple lenses, but only if it's really necessary. Otherwise, I am very happy with one body and one lens. And honestly, cropping is not a crime. With today's high-resolution sensors, you can always crop in a bit. So if you have a 28 or 35mm, you can easily crop in as if you had a 50 for example. If you have a decent camera and lens combination, no one will notice it. The main point is: do not stress over which focal length to use, use whatever you have. Don't have to overcomplicate things. If you constantly try to find the perfect lens choice from the many in your bag, you'll end up losing the joy of photography, you'll miss more shots. Trust yourself, your creative brain will help you out if you have only one lens with you and you'll grow more as a photographer.