Cleaning kit is a must have...you never know when dirt and grit or whatever fouls up your lens or camera....and you would cry if you have to wipe the dirt away with your shirt sleeve.
Hey,
Whenever I go traveling, I will always bring my either my lens cleaning kit, or my blower and static cloth. I mean you really never really know what are the weather conditions in another country or where you may be traveling.
Besides, since you are already carrying expensive lenses that weighs like hell, seriously don't think that a lens cleaning kit or blower can take up a lot of space in your bag.