Responsibilities and Obligations
Must and Have to
Must - Strong Personal Obligation
Use 'must' in the positive form to speak about strong personal obligations that you feel are crucial at the moment of speaking.
I must get trained on maintenance and repair handling before I start the job.
The manufacturer must complete the order on time by contract.
Have to - Responsibilities
'Have to' is used to indicate responsibilities at work. Use 'have to' to talk about daily responsibilities and obligation in general. 'Have to' is often confused with 'must'. The main difference is that 'have to' expresses obligation to work, family, friends, etc. 'Must' is used to indicate strong personal obligation that is felt at the moment of speaking.
'Have to' differs from other modal forms. 'Have to' is conjugated and followed by the base form.
Positive Form:
The worker has to stand behind the gate while the roller conveyor is operating.
Negative Form:
The manager doesn't have to purchase every safety device available in order to be up to code.
Question Form:
Do they have to assess the entire manufacturing industry in Fredonia?
Had to
When speaking in the past, there is only one way to express obligation: 'Had to' We use 'had to' when we speak about past responsibilities and strong personal obligations.
Example:
The boss had to buffer loading by setting a default safety lead time.
Bob had to reduce the manufacturing overheads last quarter.
Must vs. Have To
'Have to' expresses everyday responsibilities at work, or for family and friends. 'Must' is only used for strong personal obligations.
Example 'Have to' for Responsibilities:
The worker has to stand behind the gate while the roller conveyor is operating.
Samir has to reduce the manufacturing cost by reducing the cost of labor.
Example 'Must' for Strong Obligations:
I must get trained on maintenance and repair handling before I start the job.
The manufacturer must complete the order on time by contract.
The difference between 'have to' and 'must' in the negative is extreme. 'Not have to' signifies a lack of obligation. 'Mustn't', on the other hand, signifies prohibition. The past form of both 'must' and 'have to' is 'had to'
Example 'Have to' for No Obligation:
The manager doesn't have to purchase every safety device available in order to be up to code.
Example 'Mustn't' for Prohibition:
Lumbergh mustn't change the manufacturer's brand.
Milton mustn't be involved in manufacturing staplers.