When I bought my place the condition of the fireplace was a known quantity,
I wrote it off as unimportant since I don't see myself using it all that
much.

However looking at it I wonder if it is serviceable for winter or if I
should repair it before use.

I know I know it would have been best to look at it BEFORE the onset of
Autumn, but I don't live in a severe weather location, so if my gas furnace
ever gave it up, I'd still be fine.

So looking at the firebox I notice that the fire brick is cracked and the
joint compound is missing in places. The shell of the fireplace is
cinderblock and looks air tight, I'm just talking about the firebox itself
here. Should the firebox be airtight inside? Should it have no cracks or
broken bricks or is that type of condition normal and not a concern?
It was also noted when the inspection was done that the chimney is very
dirty, and looking at it it is very dirty - like an inch of ash and soot on
the walls of the chimney. I understand that this is a fire hazard, if only
because the soot can ignite and fly out the chimney and land on either the
roof or bushes or my neighbor's roof. But again am I mistaken and this
condition is normal?

It's not my intention of cashing in on my fire insurance any time soon so
I'd like to make sure I'm not overly concerned about nothing. BTW: I do
intend of having a chimney sweep come out and clean it, what do people like
that typically charge?