Two Turntables? Why

OK, been thinking about this for a bit.  Why do people own two turntables?  OK, I understand some traditional uses for a 2nd turntable.  One that is just for 78's, for example.  You may be on a journey to a set up you really enjoy listening to.  You may have even gone the route of an external power supply, isolators, base, phono PreAmp.  All of the accouterments you enjoy because, well, you enjoy records.  But if you are enjoying your LPs and you have purchased a turntable, cartridge and potentially a tonearm that you really enjoy, why do you need a 2nd turntable?  

If you go through all that effort and fun to get to a sound and system that makes you happy, and many of us have, why do it for two or more turntables.  You got a good one, why do you need a 2nd?  Maybe you play all your old LPs from High School on one standard turntable and play all your MoFi and QRP copies on the better machine.  I don't know. 

So, those of you who own more than one turntable, please let me know why you have more than one.  Let me know your thinking.  I'm curious.

Thanks