It all boils down to pre-dive planning. Take in account the type of dive, shore, boat or surf. Add to that the conditions, depths, diver skill levels and purpose of the dive (Just looking around, training photo ect.).
Rule of thumb, plan your dive.
There are numerous thread on gas and dive planning, many are very good reads.
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Dave
The plural of anecdote is not data.
Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you're a mile away and you have their shoes.