Likewise. I've never stipulated a preference of my own, because I don't have one.

I asked why they want me in there every 4K miles, and was told that because this is Utah and we use a lot of salt on our roads in the winter, this is a harsh environment. Coastal regions are also supposed to go in for oil and maintenance more often than the "recommended" 6K miles because of the salt. If I lived in a gritty environment, e.g. Saudi Arabia (we have members of the forum who do), I'd be in every 3K max, maybe more often than that during severe sand storm periods.
But watch these guys: I noticed that somehow my "service reminder" had been changed from 4K to 3K miles, and the sticker they put in the window copied that 3K miles interval. I changed it back to 4K miles and told them to write the same on my window sticker; and they did without batting an eye.

(They are just trying to hustle me through my nine free oil changes: five to go.

)