@hexxy_the_grouch @nixCraft
I go one step further than using containers for isolating my logged in sessions with sites like Google, Facebook, et al:
There's an addon called Temporary Containers that automatically isolates each new tab in FF to a container generated on the fly. Anything I want more persistent I'll just right-click and select "Open in New Container Tab" for something I manually made a container for, like a logged in gmail session.