Abstraction is useful anytime you want to reduce your 'volume' of information. For instance, you can have a set and write out all evens from 2 to 100 or write out "2n∈[2,100]_ℕ"? They both would represent the set of even natural numbers from 2 to 100, but the latter uses an abstraction.
To drive home the short answer above, you just need to ask yourself: would I rather have to carry around a million huge volumes of pictures, words, and numbers in a bag, or a smartphone that abstracts all information to binary digits and looks up information with auto-search features? Abstraction through coding and compression is used every day in information and communication technology.
But let's be humorous: One very powerful example of an abstraction is the abstraction from instances of collections to properties of collections. Let's proceed by example:
C1: A collection which contains three horses.
C2: A collection which contains three pigs.
Thus, if there are three horses, and three pigs, there must be something called 'three'. What is the nature of 'three'? What is the property 'three', and how can it be used?
Well, now you've really started thinking like a philosopher, and now, you have gone from the phenomenological properties of empirical exprience to a rational conclusion which suggests that some propositions are analytical and other's synthetic. For example, there's no empirical evidence there are three universes, yet ample evidence for the possibility of saying 'it's possible to have three animals' is true. Whether or not something can occur in threes in the universe is largely an empirical proposition. Yet, what is three? Apparently it is one repeatedly. So is the fundamental nature of things that there are dichotomies between analyticity and sythesis? How about the physical world and the world of thought? What does all of these even mean anyway?
Now, with all of these questions, it would be a good idea to have a forum to help people ask and answer these sorts of questions. Viola! Philosophy StackExchange. From one man's abstraction to a platform of philosophy to facilitate critical thinking, help corporate interests prosper, help students with logic assignments, and prevent me from having idle hands and getting myself in even bigger trouble we have come.
All by way of abstraction.