Originally Posted by mosburger
As the OP is travelling to Japan, let's take that country as an example. You can find most overseas outdoor brands and equally high quality domestic ones for all activities you mentioned. If you are outside Tokyo and Osaka/Kansai, they might have to order larger sizes from their main warehouse, but delivery times are short and customer service impeccable. Normally local products are more suitable for the environment anyway, so no harm in trying them. I've had various stuff shipped overseas after my stay was over and only rarely encountered any problems.
I can't imagine having to purchase new camping/climbing gear any time I wanted to travel internationally. Especially if one requires high-end equipment for your intended activities, the costs can become very expensive. A rock climber couldn't possibly replace his entire rack every time he wanted to travel overseas - it would be prohibitively expensive, and there's certain critical equipment one does not rent - at least not if you value your life.
I'm headed for Tanzania this June to climb Mt. Kilimanjaro and do a safari, and am struggling with the 20 kilo limit imposed by Kenya Airways. I have no confidence in finding availability of the high quality gear I want for the climb in Arusha or Moshi. And, even if I could be reasonably sure of it, I imagine it would be expensive to purchase. Rental equipment tends to be worn and of lesser quality or heavier than I would care to use.
I constantly find myself bumping up against 50 lbs. for my luggage due to the equipment demands of backcountry travel and photography.