If I had a pound for every person who asked us this question…!
There isn’t a definitive answer. As you will appreciate children learn at different paces. They may plateau or excess at different times to their peers, growth development is usually a prominent contributor to these aspects. We strongly recommend that you try not to compare your child with their sibling or peers. What one child finds hard another may find easy (vice versa).
Attending lessons as frequently as possible is beneficial than stop start or long breaks.