when to use UL or OL in html?

Question

Seems interchangable?

Answer 1

As the question asks "when to use them", I thought appropriate to offer examples of when, I usually decide to use OL when I want a series of steps, and UL when I want to offer choices:

Ordered list

Here the steps are critical for the business case, we must do the steps in this order, therefore an ordered list is used.

Checkout stages on eCommerce, these steps will be in this order.

    
shipping
    
billing
    
summary
    
confirmation

Unordered list

A user may decide on the order they choose to interact with these choices

    
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