It won't be a NiCd - they are pretty much extinct.
From what I recall, all the modern Apple stuff uses LiIon batteries. The devices are also clever enough to look after the charging process properly.
My experience with LiIon and NiMH is that their life depends on age, not number of charge cycles. The pundits may have a more precise view. Don't buy a replacement battery with a "manufactured date" several years ago.