We don't have to work overtime.
You mustn't be rude to the customers. Don't spend more than the budget.
You can't park here.
I must finish this before I go home. You have to show your passport at the border.
We shouldn't increase our prices.
You should check your emails before you send them.
You can use my office if you want.
Important not to
Not necessary to
Not possible to
Possible to
Necessary/very important to
Not a good idea to
Good idea to
