used to or past

Hello again my dear experts. I have other questions for you.

"In many cities nowadays, food shopping takes very little time. In the past, people used to go (1) to a different shop for each item. For example, you bought (2) meat at a butcher´s shop and fish at a fish market. A fruit market used to sell (3) fruit and vegetables. For dry foods like rice or beans, you had (4) to go to groceries stores." By Jack C. Richards - New Interchange- Cambridge University Press.

Can you tell me if in numbers 1 and 3 you could use the simple past without no difference in meaning. On the other hand, could I use "used to" in numbers 2 and 4 and maintain the same meaning or would the meaning become different by the change?

Thank you.

José Rocha