If I am on a site that is new to me than I will determine a plan before entering the water. I generally dive the same sites, and you have to work around the tide more than anything. My plan usually involves choosing if I am spearfishing, taking photos, or just sightseeing. I do sometimes deviate from the plan due to a longer than expected tide. In these cases I am never deeper than 40' and have more of a NDL than air supply.