Learn Hardcore Russian: Если мы не договоримся о плане, проект будет тянуться дольше, чем нужно. - If we don’t reach an agreement about the plan, the project will drag on longer than necessary.

Because the sentence has a conditional clause introduced by если. In Russian, the если-clause is normally separated from the main clause by a comma:

Если мы не договоримся о плане, / проект будет тянуться…

The comma is used regardless of word order (even if the main clause comes first).

Why are both verbs in the future: не договоримся and будет тянуться?

Russian often uses future in both parts when the condition concerns the future and the result also concerns the future:

If we don’t reach an agreement (in the future), the project will drag on (in the future).

So it’s normal that both sides refer to future time.

What verb is договоримся and why does it look like that?

договоримся is:

the verb договориться (perfective)
1st person plural, future, indicative

Perfective verbs have a simple future form (no буду/будем):

договориться → договорюсь, договоришься, договоримся…

So мы договоримся = “we will come to an agreement.”

Why is it о плане? What case is плане?

о requires the prepositional case (предложный падеж), so:

план (nom.)
о плане (prep.) = “about the plan”

The verb договориться commonly uses о + prepositional to mean “agree on/about something.”

What’s the difference between договориться о плане and договориться с кем-то?

They express different complements:

договориться о плане = agree on/about the plan (topic/result)
договориться с коллегами = reach an agreement with colleagues (other party)

You can combine both:

договориться с командой о плане = agree with the team on the plan

Why is it не договоримся (perfective) rather than an imperfective like не договариваемся?

Because the condition is about achieving a result (reaching an agreement) at some point, not about an ongoing process.

Perfective (договориться) focuses on the outcome: “come to an agreement (successfully).”
Imperfective (договариваться) would more naturally describe the process/habit, e.g. “we aren’t negotiating / we don’t usually agree.”

Here the intended idea is “if we fail to reach an agreement.”

What does будет тянуться mean grammatically? Why do we need будет?

тянуться is an imperfective verb. Imperfective verbs form the future with быть:

будет тянуться = “will be dragging on / will continue for a long time”

So будет is the auxiliary that creates the future tense for an imperfective verb.

Why is the verb тянуться reflexive (-ся)? Is it really “reflexive” here?

In form it’s reflexive, but here it’s better to think of -ся as creating an intransitive meaning:

тянуть (что?) = “to pull (something)”
тянуться = “to stretch out / to drag on (by itself)”

So проект будет тянуться means the project will “drag on,” not that someone is literally pulling it.

Could you say проект будет тянуться without будет, like проект тянется?

Yes, but the meaning changes:

проект тянется = present tense (“the project is dragging on”)
проект будет тянуться = future (“the project will drag on”)

So будет is needed for the future meaning.

What is going on in дольше, чем нужно? Why is нужно there?

дольше is the comparative of долго (“for a long time”) → “longer.” The comparison is introduced by чем (“than”).

нужно is an impersonal predicate meaning “it is necessary / needed.” In чем нужно, Russian often omits repeated words, so it’s like:

дольше, чем (это) нужно (тянуться) ≈ “longer than is needed”

It’s a common compact way to say “longer than necessary.”

Why is it чем нужно and not чем надо?

Both are possible:

нужно = “needed/necessary” (often a bit more neutral or formal)
надо = “have to / need to” (often more colloquial, can sound more direct)

So you could also hear:

дольше, чем надо with essentially the same meaning.

How flexible is the word order? Could I move parts around?

Fairly flexible, as long as the comma still separates the clauses. For example:

Если мы не договоримся о плане, проект будет тянуться дольше, чем нужно. (neutral)
Проект будет тянуться дольше, чем нужно, если мы не договоримся о плане. (more focus on the result)
Если о плане мы не договоримся, … (possible, but adds emphasis/contrast on о плане)