I'm considering writing an application that aggregates information from a fairly popular website. This application would request information from this website at a set interval. I know this is a really hard question to even "ballpark" an answer to, but what might be a good safe interval to stay mostly "under the radar"? I'm a programmer first, a human being second, and a server admin a distant third, so my knowledge of what a server software like Apache can handle as far as server load with dynamic content is pretty basic.
I know this question is EXTREMELY open ended and the answer depends on many variables, but any related experiential knowledge being shared would be very much appreciated.