Catching early flakes or redness means you can switch to a gentler shampoo right then, like @taylorp50 said about changing products. I’ve adjusted so many haircuts because a scalp was tight or tender, you just can’t get the same movement. It’s not about huge problems, it’s about making the whole service better and building client trust.
Makes total sense you stuck with it for 50 days. That consistent check probably lets you catch dryness or irritation way before it becomes a bigger problem for a client. I've found it changes which products I even reach for during the service. You start planning the cut and the care together based on what you see.
Honestly feels like maybe we're overthinking it a bit sometimes. Like how much can a scalp really change in just a few weeks between appointments. Tbh most clients would probably mention a big problem themselves before it gets bad. Seems like extra steps that might not actually change the end result much. Just my two cents.