Truism #1: The easier something goes back together, that was difficult to disassemble, the more likely you forgot something early in the process.
Truism #1B: The second time, it will be at least as difficult as you expected if not more so.
Truism #2: The less a component costs, the harder it is to access.
Truism #3: Given a choice between two potential causes, you will choose the wrong one first, 99% of the time.