It is a common practice in many countries to use the services of a private tutor. It has a lot of benefits: students have an opportunity to speak up about anything which does not seem clear to them, take their time to understand and get back to the topic as many times as they want to and, in general, build the right approach to learning. At school, teachers simply cannot ensure all of these most often than not due to the lack of one-on-one time with pupils.
A good tutor will take the time to create a study plan for each individual student to ensure that they receive a personalised service. With private tuition, students are given one to one attention throughout the duration of their lessons, which enables them to ask any questions and focus on specific areas of a subject that they may need help with.