thoughts about car battery keep hooked up OR disconnect ?

snug your positive terminal lightly a hair above being bottomed out on the tapered battery post.
Lift up at the same time you make a half turn cc to remove.Push down and twist a half turn clockwise to install.It will soon be easy to snug it on or remove when not in use.
I would never leave it connected unattended with 50 year old plus wiring on these relics.