As our UXD group does more responsive projects, we're running into an extremely high QA cost due to the complexity of our site compounded by testing multiple device and multiple breakpoints. To combat this we're considering setting a single breakpoint so that there are only 2 ranges for dev to QA. Has anyone else explored this option to manage costs? If so, what breakpoint did you choose? We're considering 760 but would other thoughts.
I would strongly recommend a minimum of three breakpoints.
Desktop screen resolutions are getting higher and higher. When desktop resolutions are now commonly at 2560px, and with 4k on the way, how could one breakpoint possibly best serve all resolutions from 760px to 2560px?
For this reason, I would set at minimum three breakpoints, loosely set for mobile/tablet/desktop, and invest in a QA service like BrowserStack or something similar to help keep QA costs down.
Well the obvious answer is - it completely depends on your content. When does your site look like it needs a breakpoint? I would also second the recommendation of at least 3. If you plan to only use two I'd go lower than 760. You might consider looking at foundation as a starting point with 0-640 as the smallest breakpoint.
It's impossible to state how many breakpoints are good and only one is most likely not enough. The number of breakpoints is best defined by Stephen Hay who said to expand the browser until your layout looks ... "bad" ... and that's where a breakpoint is set. That could mean one might just work for you. But that also means you might need nine.