I had a few questions about notation $\forall$ and $\exists$. I am posing each of the question for the former, but I have the corresponding question for the latter as well:
1) If I have only one object to quantify, is it more common to write $\forall a$ or $\forall$ $a$ (with or without space).
2) If I have more than one object to quantify, is it more common to write $\forall a,b,c$ or $\forall$ $a,b,c$ (with or without space).
3) Is using these symbols in papers on subjects other than logic, considered a bad habit? Most papers I have read outside of logic, actually spell out "For all" and "there exists".