I received a weightlifting rep plan from an app called Sugar WOD. The suggestion is simple and popular. It is referred to as 21/15/9. Choose a weightlifting exercise (e.g., bench press, lunges, curls). Do a set of 21, followed by a set of 15, and finish with a set of 9. Only you know the weight and intensity for your body. Always consult a healthcare professional and follow safety guidelines.
I have had fun with these sets. They are efficient. I see results with comfortable effort. The 21/15/9 plan is great for a busy schedule. Highly recommended!