It varies by person. Some people need more unique things than others, some people don’t really need anything but it should always be discussed *before* a session, as should anything and don’t assume you know what someone might need. If they claim they don’t need anything, don’t push that either. I, personally, don’t really need anything besides some water and a few minutes to just decompress and I’ve had so many people insist I need x or y and it almost invalidates my play, if that makes sense? “If you don’t need aftercare then you didn’t play hard enough” type comments.
Water should always be available before,during, and after a session.
Common aftercare items include: cuddling, food/snack, words of affirmation, etc.
Also, lers appreciate aftercare, too. It might not be as “important” or often overlooked completely but I’ve had a lot of lers look at me like I had three heads when I asked if they needed/wanted anything after because they have never been asked before.
I would disagree with a “ler should offer aftercare without being prompted”. You don’t necessarily know what makes someone uncomfortable. For example, Most people love cuddling. I do not, except with certain people. If a ler automatically started cuddling with me, I would be slightly uncomfortable.