I hope you read the 2 references 741cc gave you.
They point out some of the dangers and safety procedures to upgrading.
My feeling is that "if it ain't broke, don't fix it".
If you need a feature 14 has and 13 doesn't have it,
first consider how important that feature is.
Do you really need that new feature?
Can you install the feature in 13?
Don't upgrade simply because the upgrade is there.
Do it for a good reason.
Mint 13 is the Long Term Support (LTS) version.
For me that is a very big reason to stay with 13.
Mint 14 is not LTS, a good reason to not go with 14.
Jim f. 1938
Mint 13 xfce 64-bit on a diy box.
Wirth's law - Software is getting slower more rapidly than hardware becomes faster.