alternating between projects & dont remove urls

alternating between projects
when i looked before im sure i saw a way to alternate between projects, i.e. turning projects
on & off for a set period, (so you have less projects running at once so it does not overburden the system)
but when i looked again i couldnt find it.

i thought it was under
main admin screen>options

but looked a few times & couldnt find it, does anyone know where this is ?

dont remove urls


where it says
“dont remove urls – check hint”
what does that mean exactly – does it mean it wont remove the urls when it reverifies them ?
i read the mouse-over text but was’nt sure what it meant.

& “remove after 1st verification try” is greyed out & cant be selected.