Originally Posted by tdk2fe
Forever is Накогда i beleive.
Basically, difference between perfective and imperfective is that the perfective dictates a singular act that is finished or you intend to complete entirely. Imperfective is a habitual thing, or something that your in the process of doing.
Example with Imiperfective:
Кажде день мы ходим в школу (Every day we go to school)
Example with Perfective:
Завтра я пойду к врачу (Tomorrow I will go to the doctor)
Note that in the imperfective, the verb to go (Ходить) implies something you do habitually, and in the perfective case the verb to go (Пройти) denotes a specific action you plan on doing once.
Hope it helps.