First to say that the following is entirely subjective and is my take on things given my personal photographic interests predominantly in landscapes and cityscapes. Over the years I’ve learned quite a few lessons some of which I’ve learned and, on occasions, re-learned the hard way.
I think that first of all one has to look long and hard at what one’s photographic interests are, where one is going to and what weight one is prepared to carry around all day and this to a large extent will determine what one packs before setting off on the trip. There’s a strong temptation, and I know from experience, to pack in one’s camera bag the “what if” items that just add weight to one’s bag and fatigue to ones’ body. I deliberately mentioned camera bag because I think that it’s not a bad approach and one that I’ve long adhered to to pick the smallest, lightest bag that one is comfortable with and then limit the gear to what will fit in rather than pick a big bag and take the metaphorical “kitchen sink” with one. However there’s nothing wrong with packing a few “what if” lenses etc. in one’s suitcase providing that they’re well protected from knocks. I have imposed a weight limit of 1Kg or 2lbs for my camera bag and contents and I stick to this habitually.
Regarding lenses in particular I’ve recently started to pick some of my favorite shots and have them printed and put in frames and, whilst looking at them I made a personally interesting observation. The majority of my shots are taken in the moderate wide angle to standard focal-length range, no surprise there but what did surprise me was about a quarter of my chosen shots were taken with my M.Zuiko 9-18mm ultra-wide angle zoom lens, a lens that I rarely use and therefore on that basis a prime candidate to get left on the shelf when choosing what and what not to pack based, in this case, on a false assumption.
A different example would be my Lumix 35-100mm short to medium telephoto lens. There’s little point in carrying this around in my bag all day as it rarely get used but, when travelling, one doesn’t know what one will find, a good example of that being the day I visited a Zoo in Portugal and could have well done with that lens. Now, if I’d had the foresight to pack it in my suitcase and, therefore have it with me and knowing that I was visiting the Zoo, transfer it over to my camera bag for the day, that would have been perfect. Or maybe one get’s somewhere and there’s lots of great street-performers or suchlike and one wished that one hadn’t left one of one’s longer lenses sitting at home, miles away. In short, you never know what you’ll find until you get there however much one thinks that one has checked things out in advance even if it’s somewhere where one has visited many times.
Other advantages of carrying a small bag include being able to put it on the floor between one’s feet on a plane, on a tray table on a train etc. and it doesn’t attract unwanted attention such as can be the case with a bigger bag. Other things that I’ve learned over the years include always take a rain cover for both one’s camera and camera bag, a pain to travel miles to have rain stop play or worse risk damaging one’s gear, even if it’s just a plastic bag and a rubber band to hold it on the lens. Yes I know that one can buy weather-sealed cameras and lenses but they come at a premium both in terms of weight and price. A small bag such as the one that I favor will squeeze in a hotel room safe which makes me feel easier when not out and about with my gear. I’ve also taken to decanting a lens or two from my camera bag when I’m tired and putting it in a jacket pocket to take some weight off of my upper torso and distribute the weight around my body.
So, to sum things up, for me, small and light is good, take other gear but, unless one’s built like Arnold Schwarzenegger in his prime, remember that carrying around heavy kit all day that’s not being used much, if at all, is tiring and, in terms limiting one’s mobility can have a definite effect on one’s enthusiasm to move around and get the shot. I’ve certainly missed a few shots over the years by not having a certain lens with me but, to paraphrase Frank Sinatra, “regrets, I have a few but then again too few to mention” as I’ve got far more shots by doing it “My way”. 🙂 Lastly, my choice of the Micro Four Thirds camera system, with its associated small size and weight has been a great factor in helping me to get the travel shots that I want.