Charge cycles don't matter?

Every time we let off the juice pedal while driving, we are 'charging' with high voltage DC. Is that a charge cycle? We also aren't waiting 15 min to charge. Could we be too worried about when and how often we charge if we are doing it 300 times on the way to the grocery?

A full charge cycle is when the battery is charged from very near empty to full. You are talking about "partial" charge cycles, and very small ones at that. Think of it as proportional or pro-rated cycling: a full charge cycle counts against the estimated life of the battery in charge cycles, while 1/1000th of a full cycle counts as 1/1000th as much deterioration. The smallest cycles also cause less deterioration, so it may be as little as one millionth of a cycle's worth of deterioration when you let your foot off the pedal.

As Leftie says, batteries are rated for number of full-charge cycles. You use the energy whether it was supplied from an EVSE or from regenerative braking, so regen isn't accelerating your charge-cycle consumption per se. Efficiency will influence how often you have to charge and in that larger sense, knowing when to use regen and when to coast can affect your overall efficiency and so influence the number of charges you ultimately need to cover a given number of miles. I.e., hypermilers are easier on their batteries.

FWIW, back when I used to check Carwings stats, regen accounted for about 10 percent of my car's energy input.