Track grammar practice sessions.
Grammar practice is tracked on two axes at once: coverage and accuracy. Completing exercises moves coverage, but a rule is only learned when accuracy on it is high, so the mastered count discounts completed work by your current accuracy rate. That is why seventy-eight percent accuracy across ninety-six exercises represents fewer mastered rules than the raw completion figure suggests.
Coverage
Total exercises = rules x exercises per rule; progress = completed / total x 100
Accuracy-adjusted mastery
Rules mastered = floor(completed / exercises per rule x accuracy)
Around ninety percent on unseen items is a reasonable bar. Below eighty, errors are frequent enough that the rule has not yet become automatic in production.
It is effective for explicit knowledge and accuracy under exam conditions. Fluent production also needs extensive reading and speaking, where the rules are met in context.