Average for me for a comprehensive natal chart delineation (without a year's worth of transits, secondary progressions, solar and lunar returns, etc.) has always run in the vicinity of 30 pages, with everything researched, synthesized and written out by me. A "quicky" with just brief discussions of preponderances if any (the "big picture" stuff), concise house and sign meanings for the planetary placements (with few frills or nuances), and a fairly thorough major aspect analysis comes in around 10-15 pages (I just did one of that type for my daughter, who has what I would call an "easy" chart). Of course, I don't do this for payment, so I have no incentive to put in padding. I suppose full natal chart plus a one-year forecast could weigh in at around 50 pages, but that still seems like it's on the high end.
The ideal situation from a productivity standpoint would be to develop and capture all of your own thoughts on everything regarding natal and predictive analysis in electronic text files, then grab and tweak them as necessary to "assemble" any given chart. Of course, that would amount to creating a complete, personal "canned" system of astrological insights and correspondences, and could very well take years just to save a few hours on each chart. Might be worth it if it's used correctly (and you live long enough!
), and then charging for the up-front effort (what's called "sunk costs") would be reasonable.