Used to

Title include only grammar element how it write, without anithing else. Sick people often used to sleep in temples. In the description, example how to use it following the next ... 

Example don't include links for time, place, people, anithing else what can describe time. Yes, this is past form, but nothing about the time. I can see only keywords: sick, temples, often.

Withoud subject, verb and used to, also.

• [Different tense] Often is about statistics, we can use it when we don't like or can't say accurate;
• [Past] Temple is uncommon name for the buildings of the religions, now we know it's how cherch;
• [Different tense] Sick is about people who don't have a home in this context;

Without anithing, I have only one word that say about time indirectly. Yes, used to is for past ... But how to understand it from this exmaple? It's important because this is right example. It must be sufficient for.

It's tip when I can use used to, only one word temples define it.

Hmm ...

When?

• It's for the past;
  
• I haven't used word temples for my life. It defines first condition: use when subject or object in the past is unknown for me;
  
• Term #1: use it for show contrast between the past and the present, or when state or habits ends in the past;
  
• Term #2: Past simple can usually replace used to. I can exclude used to when I don't know keyword for it;
  

Did or didn't

When I need to make question or negative, I'll use did or didn't withoud difference with the past simple.

TIP

Little tip about practice say that ... people use used to instead of use in the questions and negatives. Yeasy to understand what if I know subject or object, I musn't know it when I want to ask anybody. When I like to say about past in negative.

• Directly question mean: Hey, man, I don't know about your opinion about this (subject or object), please give me the answer, this is a cause because I'm using used to instead of use.
• Directly negative mean: 

Example #1: Did you used to buy this rare car? If I'm thinking that it's in the past, to buy equal.

Example #2: I didn't used to buy this rare car. If I'm thinking that it wasn't right practice.

Hmm, I can use it for set accent what is uncommon now.

Picture & Practice

Acident Greeks on the picture is showing how to use it in common.

Question

Hm... no question on the bottom. The first doctor believed in magic. Oh, no used to here.

Why not? Magic is possible now, we don't know how to fly to the stars ... And don't know how to heal many diseases too.

Used to is right, but will be better to be accuracy with it.

How to

It's for the obsolite things.

I can use it if thinking that it's obsolite in the questions and negative. Example: Did you used to buy this rare car? I didn't used to buy this rare car.

Possible that past experience that looks wrong really isn't bad. The first doctor believed in magic.