Imperfective repetition

The imperfective aspect is not just for ongoing actions; it is the standard choice for habitual or recurring actions, as well as stating the mere fact or experience of a repeated action (General Factual Repetition).

Unbounded Repetition vs. Bounded Repetition
If an action repeats indefinitely, you use the imperfective. If an action happens a specific, counted number of times, you can use the perfective aspect to view the series as a single completed package (e.g., 'Я прочитал эту книгу три раза' - I read this book three times). However, the imperfective is just as common to focus on the experience rather than the result (e.g., 'Я читал эту книгу три раза' - I have read this book three times). Note that if bounded counts and unbounded triggers mix, the unbounded trigger (imperfective) overrides the count (e.g., 'Каждый день я звонил ему три раза' - Every day I called him three times).

Key Rules for Repetition:

• Present Tense: While present habits are typically expressed with the imperfective, the perfective non-past (future form) can sometimes be used to describe vivid present habits or potential actions. This frequently pairs with triggers like всегда or каждый раз (e.g., Иногда он придёт, посидит молча и уйдёт - Sometimes he will come, sit in silence, and leave; or Он всегда поможет - He will always help).
• Sequences: When describing a sequence of habitual actions, you typically use imperfective verbs. However, perfective verbs can be used when a sequence of actions is repeated as a 'package' (e.g., Он придёт, сядет и начнёт читать - He will come, sit down, and start reading).
• Negation: Repeated negated actions typically use the imperfective (e.g., Он часто не понимал его - He often didn't understand him). However, the perfective is quite common with negation when using the 'vivid/potential habit' pattern (e.g., Иногда он и слова не скажет - Sometimes he won't say a word; or Он никогда не забудет - He will never forget).
• Distributive 'по': To express completing one item per repetition, Russian frequently uses the preposition по with the dative case for singular nouns (e.g., по задаче - one problem each time). With the numbers 2, 3, and 4, 'по' takes the accusative case (e.g., по две задачи - two problems each time, по три раза - three times each). For numbers 5 and above, traditional grammar prescribes the dative case (e.g., по пяти задач), but modern Russian heavily favors the accusative case (e.g., по пять задач).
• Secondary Imperfectives: Perfective verbs often spin off secondary imperfectives (frequently with -ывать/-ивать) to serve as their imperfective partner. These forms take on all imperfective functions, including ongoing processes and habitual repetition. For example, use переписывать instead of переписать for 'I rewrote it every day'.
• Frequentative Verbs: In addition to secondary imperfectives, Russian has classic, unprefixed frequentative verbs (многократные глаголы) ending in -ывать/-ивать (e.g., хаживать, сиживать, говаривать). These are highly archaic and literary today, and are strictly limited to expressing distant past repetition. A major, highly common exception that is still actively used in modern Russian is бывать (to be often / to tend to be).
• Verbs of Motion: For repeated round trips, the multidirectional imperfective (e.g., ходить, ездить) is the standard choice.

Common Triggers for Imperfective:

• каждый день / год / раз (every day / year / time)
• часто (often)
• обычно (usually)
• всегда (always)

Note: The word бывало (used to / would) is a major trigger for past habits, but it frequently pairs with the perfective non-past (future tense) to vividly describe a habitual sequence in the past (e.g., Бывало, он придёт... - He would often come...).

For example, if you say 'I solved math problems every day' (Я каждый день решал задачи), you might be tempted to use the perfective aspect for completed result because the problems were solved. However, because it happened every day (unbounded repetition), you must use the imperfective form.