I'm a door repair guy, I try to help people out when there are questions about alignment of latch/strike or other door related questions.

If your door is having leverset issues, however, I'll usually just say it's a lost cause, most of the time you can replace the leverset with a new one for under $40, yourself.

I have yet to see a question about a master keyed classroom function leverset, or a dead lock with cylinder lock on it in a class aluminum door.

Sliding doors, all bets are off, I can't help you there.