I have noticed a slowing start up with my Brighton wagon, like a fuel issue has been developing.  

Is this indicative of fuel pump? How quickly would that go bad?

I have not checked the plugs though wires were not done long ago.  

Could be.  I've had several Subaru when they sat for a few days would not start right away.  If that happened, I'd turn off the key and turn it back on.  Thus cycling the fuel pump and it would start right up.  

Fuel filter 

Leaking Injector 

Could also impact fuel pressure.

smell/look around under the hood for a fuel leak.

maybe pull plugs before starting to see if one is wet from a leaking injector?

Ok, I'm thinking may be fuel filter as I have a tendency to run the car low on gas so may be scum gets in to filter.   

Could also be the check valve in the fuel pump not holding pressure.

Cycling the fuel pump does work.

I usually turn the key to on and then one or two seconds I hit start.