Highlights, roots & foils question

Hi :)
I have shoulder-length hair which I straighten with ceramic irons fairly regularly (every other day or so,) and have hightlighted approximately three times a year. (Half blonde highlights, half darker lowlights - I am naturally a mousy sort of colour.)

Firstly, does this seem fair to my hair? It feels in fairly good condition, no obvious split ends that I can see.

Secondly, when I present myself and roots to the hairdresser, foils are used and the whole of the hair, (I only have a half head streaked though - its cheaper,) is bleached/coloured. To me, it seems impossible to do it any other way (ie just the roots not all the hair,) but is this ok for my hair?

Thankyou!