Breakdown of Она ходит к парикмахеру каждый месяц, чтобы красить волосы.
она
she / it (for a feminine noun)
месяц
month
каждый
every
ходить
to walk, go on foot (multidirectional)
Questions & Answers about Она ходит к парикмахеру каждый месяц, чтобы красить волосы.
Why do we use каждый месяц without any preposition?
To express "every [time period]" in Russian, you use the bare Accusative case—meaning no preposition is needed. Since месяц (month) is a masculine inanimate noun, its Accusative form looks exactly like its Nominative (dictionary) form.
Why use the verb ходит instead of идёт for "goes"?
Because this is a habitual action that happens каждый месяц (every month). Ходить is the multidirectional verb of motion, used for regular, repeated trips. If she were on her way to the salon right now for a one-time trip, you would use идёт.
Why is it к парикмахеру instead of using в?
When you go to a person (like a hairdresser, doctor, or friend), you must use the preposition к followed by the Dative case (парикмахеру). If you were going to a place (like the hair salon - парикмахерская), you would use the preposition в + Accusative case.
How does чтобы work in this sentence?
Чтобы means "in order to." When the person performing the action is the same in both halves of the sentence (she goes in order for her to dye her hair), you simply follow чтобы with an infinitive verb (красить).