They rarely tell me what they're gonna use it for - I just give them the biggest files I prepare. I find my stuff in catalog (medium sized 300dpi - though it's printed at 150 lines), as well as magazine ads (full page at 300pdi - again, printed at 150 lines) and newsprint (name that size - 150 -125 dpi printing).

On the VERY rare occasion, I've had images on billboards - 36 dpi.

They print in so many different media I have absolutely no way to contact every printer for every job and find out specs. I just give 'em big files and the graphic designers resize them smaller to fit whatever it is that they're putting together - that's THEIR job, not mine. Mine is to give them sufficient sizes to do what they want - and they'll call me if they need it bigger.

-Lew ;-)