Laura --- Do what works for you.

I'm a fan of SPD pedals---have MTB SPD pedals on all of my bikes (road, cross and MTB). Like some of the other posters, clipping out has become instinctive for me. Second nature. When I first converted to clipless, I was extremely mindful and I anticipated situations where I thought I might need to unclip. In addition, I keep my cool and do not let myself panic. I think these are the primary reasons that I have never taken a spill due to forgetting to unclip or not clipping out in time. My one clipless incident was due to neglecting the check the tension on newly mounted SPDs. Big mistake---it was so high that I could not unclip. I told myself, don't panic....pulled up next to a parked car, stopped, leaned against the car, and took off my shoes! I used my multi-tool to correct the pedal tension and was on my way.