Having to turn and check your blind spots when driving before you change lanes or turn is second nature to many people, but it still requires that you take your eyes off the road in front of you. This can be risky, especially if you're in a crowded area. Adding blind spot mirrors can help, and the car mirrors are generally cheap and easy to install. But they can also take some getting used to, and in fact, they may be distracting at first. If you want to get these, consider how the mirrors will affect your ability to focus on certain things.
Do a Preliminary Check of Your Blind Spots
A benefit to having that extra mirror is that you'll be able to glance at upcoming traffic without turning your head. You don't want to actually turn or change lanes without really looking behind you. But you can at least see if there is a bunch of traffic next to you or coming up fast to your side before you start craning your neck. That reduces the amount of time you have to look away from the road in front.
Get Help With Parking
The blind spot mirrors can also show you a little bit more of what's around you, and that can help with parallel parking. The reflections in the blind spot mirror are often a bit smaller than in the regular side view mirror, but the overall scene that you can see in the blind spot mirror is larger, and that means you can see more of the curb and landmarks next to you as you try to gauge how close you are to the curb.
However, that reduction in size of the reflections does take getting used to. In fact, it can be difficult to focus quickly on the smaller mirror when you first start using it (or them, if you install the blind spot mirrors on both side mirrors). If you're OK with taking some time to get used to the mirrors, adding them should be fine. But if you are easily distracted and don't want to deal with the adjustment time, they might not be of benefit.
They Do Take up Space
Another issue is that the blind spot mirrors are usually stuck on top of the side view mirror -- on top of the mirror glass, that is. So you lose part of your view in the regular mirror. If your car has small side mirrors -- common in economy cars -- then the blind spot mirror might take up too much space and make driving more risky for you.
Talk to auto parts stores and to service departments about good blind spot mirrors that would fit your car and that would require little adjustment time. The mirrors can be truly beneficial if the circumstances are right.