55 chevy filler question

[wilberweb]

Hi, guys I have a question on body filler.
I am working on my fire wall filling all the holes.
and sanding like crazy trying to make every thing look as good as possible. Its a lot of work.My question is do any guys that do body work professionally work this hard on making the filler look just as good in places that cant be seen.
I.E behind a heater core or under a dashes.Places that can't be seen, or do you just fill it sand it a little and call it good.The reason I am asking its a lot of sanding and fussing over filler that wont be seen. I just thought I would ask I don't want to spend valuable time, and this much work, when I can move on to something else and spend more time on filling and making the panels that can be seen look better.

Thanks
-Larry