As a bonus, I prepend my custom aliases or scripts with my user name and hyphen (i.e helicaltwine-). It helps me recall rarely used scripts when I need them and forget the names.
I follow a similar but more terse pattern. I prepend them all with a comma, and I have yet to find any collisions. If you're using bash (and I assume posix sh as well), the comma character has no special meaning, so this is quite a nice use for it. I agree that it's nice to type ",<tab>" and see all my custom scripts appear.