Do not use someone else's dive computer.
The residual nitrogen of the previous dive profile is recorded.
If you use someone else's dive computer, you will lose control of your personal data.
Do not use anyone else's one except for safe controlled one for rental.

Reach maximum depth first and gradually reduce the depth.
Even if you do not ascend at the maximum ascent rate, nitrogen is discharged by gradually decreasing the water depth.
Nitrogen will be absorbed if the depth is gradually increased.

Take a dive computer on board when boarding an airplane.
The diving computer will respond to changes in the air pressure inside the aircraft, so keep it in a working state.
Be sure to carry it with you when diving after boarding an airplane or when boarding an airplane after a dive.