A word/phrase for something that often comes up in conversations

Question

To find a affordable apartment was a big problem. University students would often struggle to find a place to live. As I recall, that was a —————— (= popular topic of our conversations = we always talked about it).

I want a word/phrase/idiom that means ‘a common topic of conversation’ or ‘something that often comes up in conversations’.

I have here ‘hot topic’ and ‘talking point’ but they do not fit into the above context, as they mean topics such as political ones that involve arguing and taking side.

Answer 1

Collins Dictionary shows 'recurrent theme', with some examples.

In your usage, perhaps

As I recall, that was a recurrent theme in our conversations.

Answer 2

You could say that it was on everyone's lips. MW defines this as:

being said or discussed by many people

Answer 3

— ever recurring question, frequent question

As I recall, that was an ever recurring question.

Answer 4

familiar refrain

...may refer to a topic that often comes up in conversation, sometimes as a complaint.

...such as "I wish I could find an affordable place to live"

or

"The weather here really sucks."

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from Oxford Learner's Dictionary

​a comment or complaint that is often repeated

ex."Complaints about poor food in schools have become a familiar refrain."

ex. "The protest began with a small group, but then the others took up the refrain."

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It derives from an old Viennese song, which refers to the a catch phrase that repeats throughout the musical piece.

Collin's Dictionary

1. [Noun] A refrain is a short, simple part of a song, which is repeated many times.
   ...a refrain from an old song.

2. [Noun] A refrain is a comment or saying that people often repeat.

Ex. "Rosa's constant refrain is that she doesn't have a life."

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In the context of the OP, my re-write:

"To find an affordable apartment was a big problem. University students would often struggle to find a place to live. As I recall, it was a familiar refrain over pints in the local dive.

Answer 5

As an informal term, at least in BE, "a regular" (substantivised adjective) is used:

OED

8b. Something done, happening, or appearing regularly in a particular context; a regular or habitual item, feature, event, etc.

a1980 A. Powell To Keep Ball Rolling III. iv. 77 Among other regulars in the critical columns were Elizabeth Bowen's rather staid notices of plays.

2006 N.Y. Times Mag. 26 Mar. 23/1 I have a charcoal grill... I cook all the regulars on it: steak, hamburgers, chicken, corn and hotdogs.

Answer 6

Common concern in LONGMAN (as it name implies) described as one that many people share.

Monetary Stability as a Common Concern in International Law convincingly argues that monetary stability should be recognised as a Common Concern of Humankind.