Grammar "used to"

Students of all levels and all standards seem to have problems with "used to" which is more complex than you think. Some of the explanations on the internet are very poor. This is one of the best:

http://www.businessenglishresources.com/31-2/teachers-section/grammar-lessons-2/using-used-correctly/

Remember that if you want to talk or write about habits in general : what you habitually eat, what the company habitually demands etc, you do not use "used to" in any of its forms: an adverb like "usually" is sufficient.

I usually have sushi on Saturdays.

These companies normally only take on people who have a master's degree.