Is it better to use variables or arrays for storing lots of values. Which is faster? Which takes more space?
If the values are all of the same type and are related, such as a group of input or output pin numbers, then an array is almost certainly the way to store them.
Accessing values held in an array is almost certainly more efficient than using separate variables because they can be accesses using a loop structure rather than repeating code
No matter how you store a variable it will take the same space as any other variable of the same type
The more general answer to your questions is it depends on what you are doing. Do you have a question about a particular requirement or program ?