I love caulking!!! Ok , after the priming inside or out.... now comes the part that is going to make your house look as though the"best of the best" built it. Caulking seals up all the gaps, getting rid of visual black lines and holes around trim and between siding. Not only does it improve the look but it keeps the bugs and water from seeping through and causing all kinds of trouble.
I'm tellin' ya , if you haven't been caulking on your past paint projects .... that is one big reason it didn't look professional. And if you hired someone and they didn't do any caulking .... don't hire them again.
Get used to using a good"drippless" caulk gun ( not those little squeeze tubes) . And always use paintable caulk. Make sure it says paintable