Yes, especially with the lower levels (A1 and A2.1). It is important for the student to feel comfortable in class and be aware of what is going on at any point of the class and not feel lost or overwhelmed. I use a lot of translation with the beginners and also explain the grammar or pronunciation by making comparisons between Spanish and English (or other languages we both know).

With the higher levels (A2.2, B1, B2) I hardly ever use English in class unless it is really necessary.