Battery cycles on Li-Ion are different than older batteries or even say the newer NiMH. Every battery has a finite number of cycles. For older style batteries (NiMH, Lithium, NiCd, alkaline, etc...), even if you just charged the batter from say, 30% to 50%, that would count as one cycle. Li-Ion don't suffer from the same memory problems. Li-Ion really don't have a memory/cycle, per se, but to make the best sense of how Li-Ion "cycle" works, think of it as 1 cycle = sum of charges too equal 100% charged
For instance, if your phone got down to 10% and you threw it on the charger until it got to 50%, let it drain down to 20%, then put it back on and charged it to 70%, let it drain down to 40%, then charged it to 50%, that would equal one cycle.
50-10 = 40%. 70-20 = 50%. 50-40 = 10%
40% + 50% + 10% = 100% = one Li-Ion cycle
In addition, Li-Ion have a lower self-discharge (charge loss while stored) rate. You should expect near zero loss in capacity for the first 400-500 cycles. After that, Li-Ion batteries will produce 65-80% of its original capacity.