After while, firefox on my mac starts to slow down, ok I usually have a lot of tabs opened, and I use heavy extensions like firebug, greasemonkey or NoScript...
Over time I've found that the best solution I have is to just force-quit firefox, aka:
killall -9 firefox-bin
The crash manager of firefox usually allows me to restore my previous session with all that valuable tabs saved. But not always, like two minutes ago :(
Originally posted on yann.vox.com