I've been traveling a lot lately and, as a result, spending a lot of time tethering my Mac to my iPad and iPhone. Trip Mode is a Mac App that can turn off selected applications' access to the Internet. For example, I share multiple Dropbox folders with multiple people. If one of those people starts dropping some large files in Dropbox while I'm tethered, the Dropbox app will chew through my mobile data cap pretty quickly. Trip Mode lets me turn off Dropbox and any other applications I don't want accessing the Internet while tethered. The idea is simple, the execution is outstanding. When I return to WiFi, Trip Mode turns itself off and I can go back getting all my applications on the Internet.
I've written and talked about travel gear several times over the years. There is a new gadget on the market that is worthy of consideration for road warriors. It is the HooToo TripMate Elite (Amazon). This device is about the size of an older AirPort Express (the kind that would plug directly into the wall) but made of black plastic instead of white. Moreover, it is a combination of several devices useful on the road.
There is a 6000mAh Battery Charger with two USB sockets so you can charge two things at once. When you get to your hotel (or find a spare socket at the airport) you can plug it in for charging later.
The HooToo also has a built in Wireless N Travel Router. If you show up to a hotel room that just has ethernet Internet, you can plug this in and create your own little wireless network in your room. You can also plug a USB flash drive into the device and broadcast the data on it to your iOS devices using a proprietary application. While all these functions are available on devices already on the market, I have not seen someone put all of them and one device before. This is pretty nice being able to carry a travel router, battery charger, and media streamer all with one device. I haven't ordered one yet but I probably will before my next big trip.