FFT Frequency Resolution vs. Graph Update Rate of a Vibration Signal

Hello,
 
First, what I know:
The frequency resolution (Hz) of an fft is 1/acquisitionTime (e.g. if 2 seconds of data are acquired, the frequency resolution is 1/2s = 0.5Hz).
 
What I'm Wondering:
Let's say I'm displaying an acquired signal on a graph and freq res = 0.5Hz.  The graph update rate is therefore approx 2sec.  This may appear to be an application with a problem from a user's perspective.
Can I increase the update rate?
 
It seems that with vibration data (i.e. mostly non-periodic) I could create a buffer that is 2sec long.  The first data acquisition sequence will fil the buffer with 2sec of data.  Then I could just acquire something shorter than 2sec of data (let's say 1/4sec).  If I am acquiring data continuously and I push the 1/4sec of data into the front of my buffer then perform the fft again, I have effectively increased my graph update rate to 1/4sec and my users think I'm great.
Can anyone shed any light on whether or not (why/why not) this will work?
 
Thanks for your time,
Chris  
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