Having a handler and sponsor was a big deal for Reapers. Sadly, most of the girls and I never experienced having them. Both were quite similar but fundamentally different. I got lucky, but without either, newbie Reapers would have a hard time lasting in Hellsgate.
A handler was someone who acted like your backer. The best description of that meant having a shield. Should you encounter bastards that tried to pull rank and bully you. A handler would "handle" such issues.
If I had a handler, the Seeker war wouldn't have happened. Primarily because my handler would be the one to throw down with Xander. But since I didn't have one, I had to wipe my own ass and brawl with all of them. Although David sort of acted like my handler when he stopped Xander from interfering.