Ojalá la colección cambiara cada mes; así volveríamos más a menudo.

Because ojalá is used to express a wish or hope, and Spanish normally uses the subjunctive after it.

In this sentence, cambiara is the imperfect subjunctive of cambiar. That form is often used when the speaker is talking about a wish that feels hypothetical, unlikely, or contrary to the current situation.

So the idea is not just a neutral hope, but something more like:

• I wish it changed every month
• If only it changed every month

Both are possible after ojalá, but they suggest a slightly different feeling.

• Ojalá cambie = I hope it changes
  This sounds more like a real possibility.
• Ojalá cambiara = I wish it changed / If only it changed
  This sounds more hypothetical, less likely, or more like dissatisfaction with the current reality.

So cambiara fits well if the speaker feels that the collection probably does not change every month and wishes it did.

Formally, cambiara is an imperfect subjunctive form, which historically looks like a past form. But in this sentence it does not refer to the past.

After ojalá, the imperfect subjunctive is often used for a present or future wish that is unreal or unlikely.

So here cambiara means something like a present/future wish:

• that it changed every month
• that it would change every month

It is not saying that it used to change every month in the past.

Yes. Cambiase is another valid imperfect subjunctive form of cambiar.

So these are both correct:

• Ojalá la colección cambiara cada mes
• Ojalá la colección cambiase cada mes

In modern everyday Spanish, -ra forms like cambiara are much more common than -se forms like cambiase, especially in speech.

Because it expresses the result of that wished-for situation.

The logic is:

• If the collection changed every month,
• we would come back more often.

Spanish uses the conditional for that kind of result. Volveríamos is the first person plural conditional of volver.

So the structure is basically:

• hypothetical situation: ojalá ... cambiara
• result: así volveríamos más a menudo

Yes, very much so.

The sentence does not explicitly say si cambiara..., but that idea is understood. The second part means something like:

• in that case
• if that happened
• that way

That is what así is doing here. It connects the wish to its consequence.

So the full underlying idea is:

• If the collection changed every month, we would return more often.

Here así means something like:

• that way
• then
• in that case

It refers back to the first clause. The speaker is saying that if the collection changed every month, then they would return more often.

So así is not just like this here. It is more of a link between the wish and the consequence.

Volver means to return or to come back, so it emphasizes going back again to the same place.

That fits very naturally with places people revisit, such as:

• a museum
• an exhibition
• a shop
• a gallery

By contrast:

• iríamos = we would go
  This does not clearly express the idea of returning.
• vendríamos = we would come
  This depends more on the speaker’s point of view and location.

So volveríamos is the most natural choice if the meaning is we would come back more often.

A menudo is a fixed adverbial expression meaning often.

So:

• a menudo = often
• más a menudo = more often

You cannot normally turn that into más menudo with the same meaning. Menudo is a completely different word when used as an adjective.

So the phrase must stay as a menudo, and más modifies the whole expression.

Both are possible, and both can mean every month.

• cada mes = every month
• todos los meses = every month / all months

In this sentence, cada mes sounds very natural and concise. It focuses on regular repetition, month by month.

There is no major difference in meaning here, just a slight stylistic difference.

The semicolon links two clauses that are closely related:

• the wish: Ojalá la colección cambiara cada mes
• the consequence: así volveríamos más a menudo

A full stop would separate them more strongly. A comma might also be seen, but the semicolon gives a neat, clear link between the two ideas.

So the semicolon helps show:

• first, the desired situation
• second, the result that would follow

It depends on context. La colección could refer to many things, for example:

• a museum collection
• a gallery display
• a shop’s collection
• a fashion collection
• any set of items on display

The sentence itself does not tell us exactly which one. It just assumes the listener already knows what collection is being discussed.

Because Spanish normally uses the definite article when referring to a specific, known thing.

So la colección means the collection, not just a collection.

This tells us the speaker and listener already know which collection they are talking about. That is very normal in Spanish, and often more explicit than in English.

In standard Spanish, ojalá is normally followed by the subjunctive because it expresses a wish.

For example:

• Ojalá venga
• Ojalá llueva
• Ojalá pudiéramos ir
• Ojalá la colección cambiara cada mes

The tense of the subjunctive changes depending on whether the wish feels possible, hypothetical, or impossible, but the subjunctive mood is the key pattern.