How does one express frequency in Chinese?
How do you express “how many times” and “how often” in Chinese? How many times asks for a precise answer to frequency, numerically supported. “How often” can be answered vaguely. 



'how many times?' is '多少次?' or '几次?'
'how often' is '有多經常?' 



  How does one express “how long”? This can be answered in either way.


'how long' is ' 多久'


  1.你多久去游泳? How long do you swim?


你游泳游多久? How long do you swim? 

*'你游泳' is the topic 

*'游多久' is the comment


  2.你每周多少次去游泳? How often a week do you go swimming?


你每周有多經常去游泳? How often a week do you swim?

*多少次? means 'how many times?' 

*多經常? means 'how often?'


  3.你每周去游几次泳? How many times a week do you go swimming?


This one is grammatically correct. You can replace '几次?' with '多少次?' 


  4.你每天去游泳吗? Do you go swimming every day?


This one is grammatically correct. You can omit 去 and write '你每天游泳吗?' (do you swim everyday?) or you can replace '去' with '都' and write  '你每天都游泳吗?'


  5.你每天去多久游泳? How long do you swim everyday?


你每天游泳游多久? How long do you swim everyday?


  6.你每个小时休息几次? How many times a hour do you take a break?


This one is grammatically correct. You can omit the classifier 个 and just write '你每小时休息几次?' 


  7.你每个小时多少分钟休息？How many minutes an hour do you rest?


你每个小时休息多少分钟？How many minutes an hour do you rest?


  8.你每个小时休息多长时间. How often an hour do you rest?


你每小时有多經常休息?. How often an hour do you rest?

*Again, 'How often' is '有多經常';  '多长时间' is 'how long (of time)?'


  9.你多久休息. How long do you rest?


你休息多久? How long do you rest?


  10.我一小时休息三次。 I rest three times an hour.


This one is grammatically correct.

user6065 wrote: 

complements of duration (frequency) follow verbs 


That's the reason in Chinese:


'一小时多久(how long)休息(rest)' is incorrect.
'一小时休息(rest for)多久(how long)' is correct.
'一小时三次(three times)休息(rest)' is incorrect.
'一小时休息(rest)三次(three times)' is correct.


user6065 wrote: 

(adverbials precede verbs) 


That's the reason in Chinese:


'經常(often)休息(rest)' is correct. 
'休息(rest)經常(often)' is incorrect.