Yes: While my main browser is Safari at least once a day on the desktop I want to be logged into Twitter at the same time on three different accounts so Firefox

Yes: While my main browser is Safari at least once a day on the desktop I want to be logged into Twitter at the same time on three different accounts so Firefox and Chrome are the default for a single Twitter account. Although with web dev stuff I'm always looking at test sites and other sites in multiple browsers (this includes a corner of my studio which has a range of tablets in different sizes and a few different makes of smartphones). And while I can resize on my desktop, I like to hold the device to see how a website feels, animates and sounds. I guess I should also note that my testbed includes a dusty PC with ancient IE installs and that on Android I look at sites in both the stock Android browser and Android Chrome.