When repairing a laptop computer, do not put the case screws back in until you've *confirmed* the repair is actually working and holding, only put the screws back in when you are *sure* the repair is completed
if the laptop you're working on is known for a particular failure of a disposable part (AC adapter bricks, reed switches and DC-IN boards on the Apple iBook G3/G4 series), it's good to keep a few spares on hand for repairs, *especially* when the manufacturer discontinues parts for one of the models (iBook G3 series)
If the repair you're working on is going too smoothly, there's obviously something still wrong with it
the chances of a component part failing is directly proportional to how expensive/delicate/inaccesable it is
components that aren't supposed to fail (LCD display modules) have a surprisingly high failure rate
the customer will never admit they damaged their machine, even when provided with incontrovertible proof and evidence, they will always claim "it just happened" or it was a "manufacturing defect".....
....kinda' like a laptop with a cracked screen that "just happened", even though there's a clear impact dent on the back of the screen housing, or a clearly defined pressure point on the LCD panel itself
....or the laptop that still has liquid spill damage on the components, blackened and scorched components and surface-mount devices, and standing liquid still in the case, yet the customer "never drinks or eats by their computer..."