"Best practices" for objects and indexes?

Good day,

I’m wondering if there’s any sort of documented best practices when it comes to what’s being used in a given index and per object.

To clarify, I know you don’t want to set too many properties as searchable and there are some that are much better than others.

However, is there such a thing as “too many properties” for an object? I’m envisioning potentially including extra attributes that are meant just for customizing result display, but want to make sure I’m not going to approach a “ridiculous amount” of properties per object.