What is ViperWatch?
ViperWatch is an addon for hunters (written by yours truly, and inspired by Fimlys). If you are in any Aspect other than Aspect of the Viper and your mana falls below a certain percentage (defined by you), a message will appear along with a sound, alerting you to switch into Aspect of the Viper.
More importantly, however, if you are in Aspect of the Viper and your mana goes to or above a certain percentage - say, full - ViperWatch will remind you to switch out of Aspect of the Viper, using the same mechanism.
Either of these alerts, as well as the sound effect, can be turned on or off individually.