Is it worth repairing this car?

Worth usually follows the verb to be and is often used with a preparatory it. It can then be followed by an -ing clause:

• It was definitely worth making the effort to watch this documentary.
  
• It is always worth fighting for your freedom and independence.

Note that with this construction, it can be used to refer to an action mentioned in the previous sentence:

• Shall we have this car repaired? ~ No, it's not worth repairing.
  
• I shall never have any independence. ~ It's worth fighting for, you know.

This car is not worth repairing

With this structure the object of the -ing clause is made the subject of the sentence and the preparatory it becomes superfluous:

• This documentary was definitely worth watching.
  
• This documentary was definitely worth making the effort to watch.
  
• Freedom and independence are always worth fighting for.
  

Be worth a lot of money

Worth is also often followed by a noun phrase when we are discussing the monetary value of something or somebody and saying how much it or they are worth. With this construction the question forms how much and what are often used:

• What / How much do you think this violin is worth? ~ It must be worth a fortune. It's a stradivarius.
  
• He bought me earrings worth two thousand pounds. ~ Gosh, how much is he worth? ~ He's a dollar millionaire!

be worth a lot / a great deal /etc

With these expressions we are saying how good, useful or reliable something or someone is:

• She's always there for me. Her companionship is worth a great deal to me. She's worth her weight in gold.
• The government's promises and policies are not worth very much. The policies are not worth the paper they're printed on.

Note that to be worth your weight in gold and not worth the paper they are printed on are both idioms. Word order cannot be changed.

be worth somebody's while

If you say it will be worth your while to do something, it means that you will get some (financial) advantage or benefit from it, even though it may take some time or trouble:

• It would be well worth your while to invest in shares now while the stock market is low.
  
• It's not really worth my while to spend the whole day on my feet behind the counter for as little as fifty pounds.

Note from the above example that worth can also be modified by well to make the expression well worth.

worthwhile

If something is worthwhile it is well worth the time, money or effort that you spend on it:

• It was a worthwhile journey - he got to see everyone on his list.
  
• The meeting was so worthwhile and all the arguments about profit margins have now been sorted out.

Sometimes, worthwhile simply means of value and can be used in a similar way to worth with preliminary it. Compare the following:

• It may be worth comparing this year's profit margins with last year's
  
• It may be worthwhile to compare this year's profit margins with last year's
  
• It may be worth your while to compare this year's profit margins with last year's

worthless

Note that if something is worthless, it has no value or use:

• The guarantee will be worthless if the company goes out of business.
  
• With hyperinflation the local currency has become virtually worthless.