Goggles.. Do we really need them for swimming?  My answer would be a resounding yes, especially in public pools as Conjunctivitis is one of the easiest contractable illness transmitted through water.   There is no doubt that the amount of chlorine in our public pools is on the safe side but its always good to err on the side of caution and wear goggles.
Another reason why goggles is important to wear is because for a newbie or beginner swimmer, lack of vision can cause us to be more panicky and a good pair of goggles can help keep our vision clear and let us focus on enjoying our swim. 
How then do we choose the best goggles for our face?  The important element is how well the cups fit around our eyes.
While the shape of goggles cup are quite standard, there is a difference in terms of the nose bridge and the size of the cups.
We all have different face size. Our eyes are all set differently. If you are those who have the average face and eyes setting, most goggles would be able to fit you well.
But if you have deep set eyes, then you may need goggles that are not too big as the rubber surrounding the goggles may not be able to attach to your skin, create a vacuum and avoid water from entering your goggles.
If you notice, some goggles have fixed bridge attachment between the nose and some have removable ones. Those with removable ones, most of the time comes with a spare or spares. Those spares can either have different length or same length.
If you were to go shopping for goggles, you can actually ask the sales staff if you can take the goggles out of their casing to try and place it at your face.  That way, you will know whether it can fit you well or not.
You need to ensure that it fits comfortably into your eye socket and that the rubber can "suck" at your skin without any gaps and create a vacuum effect.
Another factor you may want to consider is the span of vision, i.e. how wide you are able to see. Some goggles have limited vision because the surrounding goggle is opaque. If you are a bit claustrophobic, it would be good to get one that has wide vision, i.e. the surrounding goggle is not opaque but clear as well.
For those who are short sighted, you can opt to get optical goggles which are either the same degree as your glasses or -0.5 from your usual degrees.