T-mobile coverage is awful in West Virginia.

Cell towers are not cheap! They are expensive to build and maintain
and usually require all sorts of local permits which are getting
harder and harder to get. It's also not cheap to get roaming
agreements with other carriers. The company has to balance the
revenue it might generate against the cost. It may be that there are
just not enough T-Mobile customers to warrant the cost.

In my county, they shot down new towers being built by T-Mobile and
Sprint. As a result, our T-Mobile coverage is practically zilch and
on our North Shore, Sprint is poor at best.

T-Mobile has always lacked coverage in ex-urban areas. In Georgia,
they have virtually no native coverage in most of the southern portion
of the state, and very little roaming on AT&T. Can't count how many
times my phone said "emergency calls only" when it would stray onto an
AT&T cellsite but no T-Mo signal far and wide.

Bottom line is the PCS band carriers suck in smaller towns and
especially in between. T-Mobile limits their roaming onto other
carriers which keeps their service cheaper than other national
carriers, but if you want solid coast-to-coast coverage, Verizon and
AT&T are the only two real choices, and well, Sprint if you can put up
with atrocious customer service.

sorry to say this is very true your better off with at&t i used to be
a tech support rep for tmobile

I recall reading a while back that T-Mobile no longer has a roaming
agreement with AT&T. That means their coverage area is even worse than
before. As for putting up more towers, that is not as easy as you
might think. It requires permission of the local government and
citizens as well as a location to put it. It is also not cheap for
them to put up a new tower. I recently looked into switching to
T-Mobile and was very disappointed with their coverage area.

are used as additional phones. I know of several people who use their
cell as their only phone. They have no landlines at all!

My sister is in college now and if she had no cell phone, she could
not call us at all because the dorms are no longer equipped with
phones.

So no, it is not necessarily a "luxury" item.