My water changes also depend on the tank. I gravel vac/water change a minimum of ~20% once a week, but I test a couple times a week. If my nitrates start climbing, I do a small water change (doesn't happen often). Really, those tests are your guide to water changes. ANY ammonia or nitrites, higher levels of nitrates, is a sign that a water change is needed. Doesn't mean if none shows up, don't change the water; rather means changes aren't needed as frequently. But keep in mind, anything that goes into the tank STAYS in the tank unless YOU remove it. Hence my weekly gravel vacs/water changes.
Since I run 2 bio-wheels, I do change my filter media when its really clogged. There reaches a point where rinsing simply cannot remove the fine debris stuck in the spaces, and it decreases the effectiveness of the filter media. I went out and bought some plan old filter media instead of the expensive pre made filters. Works just as well and is cheaper.
As for tank set-ups and initial water changes, again I follow test results and not a set rule. I've been fortunate to either have Bio-Spira or mature filter media to kick start my tanks, but even then was doing regular water changes from the get go. Ammonia and nitrites are deadly to fish; I see no reason to subject the fish to em, so I dilute with the water changes.