Testing

These men must also first be tested; then let them serve as deacons if they are beyond reproach. - 1 Timothy 3:10

Paul is not saying that you give them a try as a deacon, but that the testing would be a thorough examination of the character, lifestyle, ministry etc. then if they are above reproach let them serve.
The beyond reproach phrase causes some concern to many. He cannot be referring to a sinless life (for all have sinned) but rather to a life that is free from flagrant, public, or frequent sins min the sight of men.