I also love TripMode. Uses a kernel extension which some users may dislike but so nice to turn off Dropbox/Google Drive/Arq/iClouds backup services while tethering at Panera

I second this! TripMode is a great product if you frequently tether with your phone, or connect to wifi networks with limited bandwidth (airplanes).

Third it! Trip mode is great. I tether from my phone a lot and need to protect my data from background usage.