I definetly periodize my speed work. I guess what I was trying to say is that "speed" has different components, but I think it is easy to get drawn into a corner rather than looking at how the sum of the components produce the desired effect: Increased speed.
How do I periodize my speed work? Nothing revolutionary. Acceleration development–> Max V–> Neuromuscular Speed Endurance (one of my strange workout protocols). For my 2/4 guys, I'll start doing some pseudo-Special End. 2 work earlier in the year, but it's not ridiculously fast just because of how far along we are in the macro and weather conditions here in the Northeast. It's more like race modeling-stuff…Like KT, however, I believe that some of the best Special Endurance sessions are competitions.