Just started to use watercolor and got a set of 6 Schmincke Horadam watercolor, i decide to get some more and looking at color table i found out that colors have a lightfastness categorization.

I thought that all artist grade watercolor was at top of lightfastness grade.

It says "The rating of lightfastness as a 5-star-system ist based on blue wool scale. This allows a more precise differentiation especially in the more lightfast categories."

few color has 1/2 star on lightfastness scale and some new colors has "Without evaluation of lightfastness."

should i consider the lightfastness star when choosing color or bottom line is more than enought?

how minimum star should it has a color to have a durability over time if kept indoor, not direct sunlight exposition?