My local diving is done at around 6000', so every local dive is an altitude dive. My computer (Oceanic Veo 100) automatically adjusts for altitude but before I got it I just did the theoretical adjustments to the tables. I bought a slate that has the conversion tables printed on the back and used them when planning dives. I love my computer but using the tables with altitude conversion is not hard, just make sure you know how to use them because you do need to make a few adjustments.