I have 5 outside doors, all with $18 kwikset deadbolts. I want to increase security, and those are prety terrible. I figure I could save a heckova lotta money by just making all the rear and side doors one sided (no key hole, just a plate). Would there be a downside to this? I've rented houses and apartments with rear doors and didn't even have the key for them. It really doesn't seem like there's a gain in being able to unlock anything except the fornt and garage doors.