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.

Ag insider logo xs@2xpgaulke60
The most TT's have only ''place'' for one tonearm. But if one
use MM's and MC's one need two different tonearms. So either
one TT with two tonearms or two TT' s with one arm. Except,
of course, those who collect TT's for their own reasons. 
I have a modern table with extremely accurate speed that sounds very clear. It's my daily driver and sounds superb.

I have a classic TD124 for that rim drive magic, and to play all of my 16's and 78's (ok, joking, no 16's). It's a classic, and has its charm but the sound is certainly more veiled than the other 'deck. It has a replaceable headshell, so I can easily swap between mono, stereo and 78 styli. That's worth holding on to--for now. 
I replaced a modified Project manual turntable with a Technics automatic from the early 80's. I really enjoy the auto shut off, but miss the more exacting sound of the Project. I may add a decent quality manual in the future for serious listening, but I will keep the Technics for my more casual needs.
My reason was to run a second tonearm one light and one heavy. I don't care for any of the two arm turntables I can afford. I like big greg's idea of using a second table for used records. 
Once I get enough loose change I plan on putting a Reed 5T on a Grand Prix Monaco 2.0. That will negate the need for a second arm and table entirely.

"I replaced a modified Project manual turntable with a Technics automatic from the early 80's."
May I ask which Technics is that?