Primary school is the child's most important time. This is where the foundations are laid for later schooling and the future. That's why it is all the more important that this knowledge is firmly established.
The child does not necessarily have to have bad grades in order to decide in favour of tutoring. Often, clever and hard-working students drown in the crowd, they cannot be supported enough by the teacher.
Tutoring is even more important if the child has poor grades. Often the reasons are manifold. At school, the teacher cannot look after individual students. For this reason, it is important to send the child to private tutoring as early as possible so that the problem does not spread any further. Here, the child receives targeted support. Usually all that's needed is a second explanation, a different perspective and it clicks!