Browsers these days have settings which automatically unload tabs to make sure you don't run out of RAM. I personally don't run into issues with 16GB of RAM, so I don't have those settings enabled.

> and never turn off your computer nor close your browser. I like being able to read my bookmarks a week, or even a month later.

Browsers allow persisting the set of windows and tabs you have open across sessions, so this isn't an issue. I probably have a few hundred tabs open at any given moment across a few subject-specific windows, some of those tabs several months old, and I close my browser and shut down my computer all the time. Firefox simply restores the windows and tabs when I open it, so it all works out just fine.