What is the best practice to show old value when editing a form in Laravel?

Function old have default parameter if no old data found in session.

function old($key = null, $default = null)

You can replace expression in template with

value="{{old('title', $dog->title)}}"

I know this has already been answered but I thought I would leave a little snippet here for others in the future.

Setting old value on input as @ikurcubic posted can be used the same way on radio button or select:

<input type="text" name="name" value="{{ old('name', $DB->default-value) }}" />

Select option:

<option value="Jeff" {{ old('name', $DB->default-value) == 'Jeff' ? 'selected' : '' }}>Jeff</option>

Radio Button:

<input type="radio"  name="gender" value="M" {{ old('name', $DB->default-value)== "M" ? 'checked' : '' }} />

Another way of doing it; write a small if statement to determine which value should be evaluated:

@php                                  
if(old('name') !== null){
    $option = old('name'); 
}
else{ $option = $database->value; }
@endphp

<select name="name">
   <option value="Bob" {{ $option == 'Bob' ? 'selected' : '' }}>Bob</option>
   <option value="Jeff" {{ $option == 'Jeff' ? 'selected' : '' }}>Jeff</option>
</select>


<input type="radio"  name="gender" value="M" {{ $option == "M" ? 'checked' : '' }} />

<input type="radio"  name="gender" value="F" {{ $option == "F" ? 'checked' : '' }} />

Setting old value of input with an array name e.g name="name[]":

<input type="text" name="name[]" value="{{ old('name.0) }}" />

This will give you the old value of the input with an index of 0.

I have tested this and it works.