It's never any fun when your dive gets cut short because your buddy's air is low.
It's even less fun when you're that buddy.
Want to make your air last an hour or more? Read on to get the tricks all the top divers use.
First off, keep in mind what it means to make your air last. You don't necessarily need it to last an hour, all you need is to make it to your decompression limits. For instance, that's just 40 minutes for a 66ft/20m dive (following the PADI recreational dive planner). Reaching some of these limits may not be possible, but it gives you a number to aim for.
Next, remember to track your air consumption in your log book. Even if you don't take your log with you, it's hard to keep all your start and end numbers in your head for a multi-dive day. Bring something to jot it down on, cause it's impossible to judge your progress without some sort of written record. Dive computers make this easy nowadays, since they track your dive time.
So you've got a goal and a log of your progress, here's some tips for getting those numbers up!
Relax. Diving is fun. You should never be tense or wearing yourself out during a dive.
Keep your breathing regular. It sounds obvious, but consistent breathing improves your air consumption. Try to catch yourself if you're ever huffing away, and remind yourself to breathe slowly, counting your breath if necessary (in-2-3-4, out-2-3-4-5-6-...).
Regular exercise. I could list all the benefits this has, but we're interested in air consumption. Plain and simple, the more fit you are, the better your body utilizes oxygen, and the more it takes to get you winded.
Quit smoking. If we ignore that it will most likely kill you, smoking also kills your air usage. Smoking trashes your lungs, which is terrible for air consumption.
Yoga / Meditation. Diving is already compared to meditation under the sea. I have no doubt a big part of that is hearing your breathing through the regulator, making you mindful of your breath. Having a regular yoga and/or meditation practice teaches you mindful breathing. Who knows, it may make you enjoy your diving even more. (as if that were possible!)
Use your snorkel at the surface. Whether you're swimming to a buoy or just waiting for your buddy to get off the boat, switch to your snorkel. No need to burn through precious air when there's plenty of it above the waves.
Buoyancy control. Proper weighting keeps your body horizontal, reducing drag and slowing air consumption.
Use any or all of these tips as they apply to you to improve your air consumption and maximize that bottom time!