What are the rules for the order of time adverbs? I have some doubts about the sentence order for time adverbs.
Note: Time adverbs tell us when an action happened, but also for how long, and how often.
English examples:

When: today, yesterday, later, now, last year.
For how long: all day, not long, for a while, since last year.
How often: sometimes, frequently, never, often, yearly.


I know the usual sentence order in Mandarin is:



S + Time + VP



But when we want to put emphasis on the Time, this structure is also allowed:



Time + S + VP



However, structure 2 does not seem to apply for all adverbs of time. I know time adverbs expressing frequency and duration follow a different pattern. But here I am thinking of time adverbs indicating habitual actions such as 经常 (often), 总是 (always) or 一般 (usually). For example, in  here they explain we can not say structure 2:

 经常他不吃早饭
Jīngcháng tā bù chī zǎo fàn. 

But only structure 1:

他经常不吃早饭
Tā jīngcháng  bù chī zǎo fàn.
He often skips breakfast.

On the other hand, I have seen some other examples of time adverbs indicating habitual actions following structure 2 with &quot;每 + Time + S + 都&quot;, such as:

每天我都运动。
Měitiān wǒ dōu yùndòng.
Everyday I do exercise.

Q1: Which adverbs of time can follow structure 2?

Q2: When there are several adverbs of time, is there a rule indicating their order?
For example, can we rewrite the following examples:



周末我经常去学校。
Zhōumò wǒ jīngcháng qù xuéxiào.
I often go to school on weekends.

(with time adverbs: 周末, 经常), such as:

我周末经常去学校。?

Or:

我经常周末去学校。？




我一般12点睡觉。
Wǒ yībān 12 diǎn shuìjiào.
I usually go to bed at 12 o'clock.

(with time adverbs: 一般, 12点), such as:

我12点一般睡觉。？
You said:

&quot;However, structure 2. does not seem to apply for all adverbs of time,
in particular for some time adverbs indicating habitual actions such
as 经常 (often), 总是 (always) or 一般 (usually). &quot;

You probably mixed up time words with frequency words. Those are quotes from your links on &quot;ChineseGrammarWiki&quot;:

Remembering where to put the time words, such as &quot;yesterday,&quot;
&quot;tomorrow,&quot; &quot;this week,&quot; etc. in a sentence is really important in
order to speak Chinese correctly.
Time words can appear in one of two positions in the sentence in Chinese: either &gt; at the beginning of the sentence (before the subject), or directly after the
subject. The structures are:
Time + Subj. + Verb + Obj. 
Subj. + Time + Verb + Obj.
From Time words and word order


&quot;...常常 and 经常 both can be used to express frequency...&quot;
From Comparing changchang and jingchang

So, that answers Q1: 
&quot;Which adverbs of time can follow structure 2?&quot; 
In this case, the answer would be &quot;none&quot;, since the words mentioned in the Wiki that relate to time, are proper nouns (They are names identifying different parts of time), not adverbs.
Let's look at your sample sentences given in the &quot;examples&quot; section of &quot;Q2&quot;:

周末我经常去学校
我一般12点睡觉

When we remove the last section from the sentences for simplicity, then identify the role of each word, we get this:

&quot;周末我经常&quot;

&quot;周末&quot;: proper noun of time
&quot;我&quot;: proper noun of subject
&quot;经常&quot;: adverb of frequency


&quot;我一般12点&quot;

&quot;我&quot;: proper noun of subject
&quot;一般&quot;: adverb of frequency
&quot;12点&quot;: proper noun of time



Because those 2 formats are accepted, without changing the meaning of the sentence, and because frequency words cannot be located at the beginning of a sentence (As mentioned in Q1), therefore, the answer to Q2: 
&quot;When there are several adverbs of time, is there a rule indicating their order?&quot;
is &quot;Yes&quot;.

Hope this helps. If not, correct me.