Level 5 Unit 5 -
'Musn't' vs 'Don't have to'



'Don't have to' is permissive. It means doing something is not an obligation.
I don't have to work tomorrow so we can go to the country.
John has a car now so he doesn't have to take the train every day.

It doesn't tell you whether the action is actually done:
Mary doesn't have to phone her mother every day - but she always does!
Employees don't have to start at eight in the morning so I always go in at nine and stay later.

Notice the infinitive here:
It's nice having a dishwasher and not to have to do the washing up.
And a gerund:
The kids go swimming every day. They like not having to wash!
These are interchangeable. You can also say:
It's nice having a dishwasher and not having to do the washing up.
The kids go swimming every day. They like not to have to wash!
Both are OK.