The dead walk among us! Run for your lives!

Jokes aside, i think what that person was saying is that you shouldnt recast buffed DoTs until they expire. When you apply a DoT, the game snapshots your current buffs so that if a buff expires before the DoT does then the DoT remains at the strength it was cast at. When you re-apply the DoT the game rechecks your buffs, and you might lose some strength off it if you reapply too soon. So the person you quoted was probly advising letting a buffed DoT expire before reapplying to assure full strength all the way through. Probly. Its also possible some mechanics have changed in the 2 and a half years since that post.