I'm going to take a little break from computers to talk about
cameras from my perspective as a former camera store manager. Granted,
it was back in film era, but still, cameras are cameras.
What do you want to use the camera for? What are you going to take
pictures of? If you don't answer these sort of questions yourself, the
salesperson will ask you. This process is known as "qualifying" the
customer and is used most often when a customer has no idea what camera
they want to buy.
The more research you have done prior to going into the store, the
more pleasant your buying experience will be. There are more than
enough brands and models to confuse even the salesperson. A good
salesperson is not a brand nazi, someone who owns Nikon or Canon
equipment and tries to sell every customer that brand of camera.
It is a fair question to ask a salesperson what camera they own and
why they own it. It is also fair to ask if they are on commission and
if there is a special commission on the camera they are trying to sell
you. The manufacturer will sometimes offer sales staff a commission on
a particular item in their line. Sometimes the store management will
offer commissions (known as "spiffs" back in the day) of their own or
on top of the manufacturer's spiff.
Salesman on commission are hard closers, and you may feel that it is
less stressful working with an hourly employee. However, if you think
that working with Del at Walmart is a picnic, remember that Del doesn't
care if you buy a camera or not, and for him, one camera is pretty much
like any other.
A salesperson on commission wants to (very much wants to) sell you a
camera and is willing to find out the exact camera that will fit your
needs. This sort of salesman knows the differences between cameras and
can explain (in detail) why the features of one camera are better for
the type of photography that you are going to be doing.
While there are folks who buy cheap cameras that will disappoint
them, it is more likely that folks will purchase too much camera for
their needs. I suppose you could use a Leica to photograph your family,
your pets, and Aunt Betty's birthday, but I'm thinking that since a
Leica costs around $6,000, it might be a waste of money.
There is a big dividing line in my mind that separates the camera
buying public.
Interchangeable Lenses
Some cameras have a built-in lens (usually a zoom lens) and a more
compact size than a camera that has a mount for interchangeable lenses.
Customers who need a less expensive camera that can record the major
events in their lives typically do not need a camera with the ability
to change lenses. I refer to this type of camera as a point-and-shoot,*
since that is what the camera is designed to do. Don't get me wrong,
there are some very high quality point and shoot cameras out there, but
they are designed for a customer who wants to take pictures and not
have to worry about the process.
Let's compare this type of camera to the flood of mobile computing
devices that are now entering the computer market. Smartphones, iPods,
tablets, and netbooks all do computer-y things, but for maximum
versatility, you need a PC. Mobile devices are designed to put a lot of
PC features into a portable device, but they can't duplicate a
traditional PC. Similarly, a point-and-shoot camera has a lot of the
features of high-end cameras, but not all of them, and, most
importantly, it doesn't allow you to change lenses.
I use interchangeable lenses so that I can photograph sports or
wildlife (extreme telephoto lens). I use a wide-angle lens to
photograph the exterior and interior of buildings. And I use a macro
lens to photograph objects at life-size.
A point-and-shoot camera allows you to eat a snack, but the
interchangeable lens camera allows you to eat the whole banquet.
I'm speaking in generalities, but when buying a camera, everyone has
different needs. Just like when you buy a computer, you should
concentrate on buying a camera that will suit you and not your friends,
fashion, or the salesman's preferences. In a technical field, the more
education you have in the field, the better. A truly knowledgeable
salesperson is very helpful, but don't be afraid to try different
stores to find one. 
