How it Works: Location, Location, Location
One methodology for programming is to enable the desired service types, enter the zip code, and scan (actually all of this after updating the database to the most current).
If the scanner stops on a channel you don't want to hear again, press AVOID twice to permanently avoid it.
If the scanner stops on a department you don't what to hear again (including all the other channels in that department) press DEPT then AVOID twice.
If the scanner stops on a system you don't want to hear again (including all departments/channels in that system) press SYSTEM then AVOID twice.
Relatively quickly, you will be scanning almost entirely things you want to continue to scan. If desired, you can then turn that into a Favorites List that you can further fine tune by MENU --> Manage Favorites Lists --> New Favorites List --> Add Current dB Channels
You then rename the FL, add quick keys, etc. Easiest at that point to use Sentinel to read from scanner, then edit in Sentinel before writing back to scanner.
One advantage of this method is that you might find some agencies that were "off your radar" that you would actually be interested in scanning.