Я не люблю медлить, когда дело касается билетов: хорошие места быстро заканчиваются.

In Russian, любить / не любить + infinitive is a very common way to say to like / not like doing something.

So:

• Я люблю читать. = I like reading.
• Я не люблю ждать. = I don’t like waiting.
• Я не люблю медлить. = I don’t like delaying / hesitating.

This structure is very natural and often corresponds to English I don’t like to... or I don’t like ...-ing.

Медлить means to delay, to hesitate, or to be slow to act.

In this sentence, it does not mean simply to move slowly. It means something more like:

• to put off acting
• to wait too long
• to hesitate instead of deciding

So Я не люблю медлить suggests: I don’t like dragging my feet or I don’t like waiting around too long.

Когда means when, and here it is used in a general sense: whenever it comes to tickets.

The sentence is describing a habitual or typical situation, not a pure condition:

• когда дело касается билетов = when it comes to tickets
• если дело касается билетов would sound more like if it comes to tickets, which is less natural here

So когда is the better choice for a general rule or repeated experience.

Literally, дело касается... means something like the matter concerns... or the issue touches on....

But as an expression, it often means:

• when it comes to...
• as far as ... is concerned
• regarding...

So:

• когда дело касается билетов = when it comes to tickets

This is a very common and useful phrase in Russian.

Because the verb касаться requires the genitive case, not the accusative.

So:

• касаться чего? = to concern what?
• билеты is nominative plural
• билетов is genitive plural

That is why the sentence has:

• дело касается билетов

Other examples:

• Это касается всех. = This concerns everyone.
• Вопрос касается работы. = The question concerns work.

So this is something you simply learn with the verb: касаться + genitive.

In the expression когда дело касается..., дело is part of a fixed idiomatic phrase.

Literally it is the matter or the issue, singular. Russian uses this singular noun in the set expression:

• дело касается... = the matter concerns...
• idiomatically: when it comes to...

You usually do not change it to plural here. Think of it as one chunk of language.

The colon introduces an explanation or reason for the first part.

So the structure is:

• I don’t like to delay when it comes to tickets:
• good seats run out quickly.

The second clause explains why the speaker does not like delaying.

Russian often uses a colon this way, especially in written language, when the second part clarifies or justifies the first.

Because хорошие места is the subject of the verb заканчиваются.

The basic idea is:

• места заканчиваются = seats run out / become unavailable

Since места is the subject, it stays in the nominative plural:

• хорошие места

If it were in the genitive, it would be playing a different grammatical role.

So here:

• хорошие = nominative plural adjective
• места = nominative plural noun

Here заканчиваются means run out, sell out, or become unavailable.

Literally, заканчиваться often means to come to an end. But with things like tickets, seats, money, supplies, etc., it can mean to be used up or to run out.

So:

• хорошие места быстро заканчиваются = good seats go quickly / run out quickly

Very similar examples:

• Билеты быстро заканчиваются. = Tickets sell out quickly.
• Деньги заканчиваются. = The money is running out.

Russian often uses the present tense to express a general truth, habitual situation, or what usually happens.

So this sentence does not mean the seats are running out right now only. It means:

• good seats tend to run out quickly
• that’s what usually happens

This is the same idea as English present tense in sentences like:

• Good seats sell out fast.
• People get impatient.

The verb заканчиваться is imperfective, and that fits because the sentence describes a general recurring fact, not one completed event.

Compare:

• заканчиваться = imperfective, to be running out / to tend to run out
• закончиться = perfective, to run out completely / to be finished

Here the speaker is talking about what usually happens with good seats, so the imperfective is natural:

• хорошие места быстро заканчиваются

If you used the perfective in a specific context, it would sound more like one completed future result:

• Хорошие места быстро закончатся. = Good seats will run out quickly.

Literally, yes:

• хороший = good
• место = place

But in the context of tickets, места usually means seats.

So хорошие места means:

• good seats
• better seats
• sometimes even the best seats, depending on context

This is very common in Russian when talking about transport, concerts, theaters, cinemas, and similar situations.

Yes, definitely. The sentence is natural, but Russian offers several alternatives.

For example:

• Я не люблю тянуть с билетами: хорошие места быстро заканчиваются.
  = I don’t like putting off buying tickets: good seats go quickly.

• Когда речь идёт о билетах, я не люблю медлить.
  = When it comes to tickets, I don’t like to delay.

• С билетами лучше не медлить: хорошие места быстро заканчиваются.
  = It’s better not to delay with tickets: good seats run out quickly.

These all express a similar idea, but your original sentence is perfectly idiomatic and clear.