first, i miss the option 'never' in your poll
i installed LMDE in October last year and never had to reinstall it. What
means, it never was broken.
second, there were few situations i couldn't boot the graphical mode after an update. But booting the recovery mode
for finding a fix always was possible. If it happens you can't boot after an update, take a look atviewtopic.php?f=141&t=67502
or ask in the forums.
third, it's always a good idea running a rock solid system such as LinuxMint 9 LTS beside your LMDE. If you need time
for finding a fix for your LMDE that seems to be broken, it' s much easier to find a solution if you have a working system.
I believe in everything, except humans.
LM9, Debian Testing Xfce, Debian Sid Xfce - CPU/Amd64 2,6Ghz, Graphics/Nvidia 9600 GT, Sound/SB Audigy4 emu10K1