5. Make your deepest dive first and plan successive dives to progressively shallower depths. During a dive, start at the deepest point and work your way shallower. As recommended by the dive medical community, avoid going from shallow to deep. Computers will continue to give you no decompression times if you break this guideline not because it's okay, but because it's better than no data at all. Avoid making multiple deep dives with short surface intervals between them.

6. Stay well within computer limits. Always try to have five or more minutes no decompression time remaining. If you let it near or reach zero, you've pushed the limits even though you'll have plenty of no stop time when you ascend to a shallower depth.

7. If your computer quits, you may need to stop diving for 12 to 24 hours. If it quits during a dive and you've been staying well within the no decompression limits, ascend immediately to 5 metres/17 feet, make a safety stop for five minutes or more and surface. You can't simply grab another computer because it won't know how much residual nitrogen you haw. Follow the manufacturer's instructions.

8. Take the RDP for backup on dive trips so you can resume diving the next day if your computer fails. If you computer fails and you've been tracking your depths and times. and your dives stay within RDP limits, you can continue diving using the RDP. Otherwise, you'll probably have to wait until the next day for residual nitrogen to clear before you resume diving. Although it's computers you dive resort to have dive computers you cant rent, don't count on it. Take your RDP so you can be sure you won't miss out. Preferably, take The Wheel so you can plan multilevel dives that maximize your no stop time.

9. Keep thinking. Dive computers can fail just like any other piece of' equipment. Don't blindly accept everything your computer says, especially when it appears way out of line with a buddy's computer or your previous experience. Read the manufacturer's instructions completely before using your computer, and follow what they say. You can learn more about the theory and use of dive computers in the PADI Multilevel Diver course.