It's hard to say, as individual areas of electronics can differ greatly. But I can say that in my 20 years, I've had to calculate an actual integral exactly zero times as an example. Same with Fourier transforms and other advanced stuff. Maxwells's stuff - forget it.
That being said, the concepts are important and I've had to use them many times.
Day to day math for most engineers is generally little more than ohms law and other basic formula.
mkissin mentioned power electronics, and that's probably one area that would be different and require more math.
As for embedded systems, the math should be very minimal. But it would not be uncommon to have to implement an FFT routine for example. But rarely would you code it from first principles for example, you'd just use a pre-written routines.
So generally speaking, all that first principle stuff you'll rarely if ever use, but knowing what to expect and the concepts are important.
Dave.