Dual Monitors-Can one just be used for editing?

I am upgrading from a 6 year old Macbook Pro to a Mac mini I7.  I have a HPLP3065 30" monitor.  It has served me well.  I used my Macbook as the 1st monitor in Lightroom but edited on the HP.  MY QUESTION-Could I use a relatively inexpensive monitor for my Lightroom and then use my 2nd 30" HP as the main monitor?  I even think I would get a 25" monitor to go with the HP 30".  Does anyone else do this?

Thanks,

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Scott
www.rscottsherman.com