Anything you can catch a glimpse of from a window or other opening once buttoned up is painted

Now the level of detail I paint it to varies. If it is something that can't really been seen properly I am not going to go crazy detail painting it, but will at least get the basic color laid down

for example, I was building the 1/72 Airfix B-25 and 1/72 Academy B-17 and both have interior stuff, most of which can barely be seen, and even then would require interior lighting to be seen well. I will at the very least spray it all with the interior color even if I do not bother detail painting all the various controls etc..

On the other hand, if I am closing up the gear doors or bomb bay doors and there is no window or open door I do not bother painting that area and in some cases, unless parts are needed there for structural integrity I won't even bother gluing in the parts and will save them for the greeblie bin