Another source of information will be the bills and receipts that you have received over the past quarter. If you have not kept such documents and records before, then now is a good time to start. The good organisation of your important financial documents, and orderly filing of bills and receipts, will stand you in good stead for controlling the family budget when it is set.
The next thing to look at, what are the goals of the client? Many clients like personal trainers simply to help them work out, no specific goals but general overall fitness. For these clients, percentages are probably unnecessary as you as the trainer can monitor their intensity and effort by watching. If it is an athlete preparing for their sports, intensities will give you a great guideline to go by and allow you to accurately pick a weight for their work sets that will increase their potential for strength.