Keeping multiple tabs open while browsing uses lots of memory and slows your entire system down. But it doesn't have to.
Install NeverCrash to substantially reduce the amount of memory and CPU usage that Firefox takes up by "pausing" tabs that you aren't currently using but don't want to close.
NeverCrash lets you organize lots of tabs without having them slow down your computer.
The ability to keep lots of tabs open at once while browsing is a great feature of Firefox. Unfortunately, having all those tabs open uses a huge amount of memory and CPU, especially if any of those tabs have Flash components running. They can slow down your computer dramatically. If you're on a laptop, this CPU use can quickly burn through your battery life even when Firefox is in the background.
With NeverCrash installed, all of your tabs have a "pause" button that appears when you hover on the Favicon (the image beside the tab title). Click "pause" to remove a tab from memory, while keeping the tab in place. Hover again to reload the tab (you'll need to be online to reload). Other features include the ability to right click on a tab and chose to pause or unpause all tabs at once.
NeverCrash is particularly useful when you have a few videos open that you don't want to watch right away but don't want burning memory and CPU in the meantime. Just "pause" the tabs and reload them later when you're ready to watch.