Most business owners know how they want to run their business. To a large extent this is based on the business owner‘s personal values, ethics and interests. Sometimes the day to day problems pile up at such a rate the owner loses sight of what they wanted to achieve as they get buried under layers of demands on their time. Most people would not consider carrying out a health check on themselves. Instead they consult an external expert who will take an objective look at them and provide impartial advice. In business a similar route should be followed as anyone involved in the day to day running of a business may not notice a significant problem due to familiarity. The old adage about the value of a fresh pair of eyes is true in business as it is elsewhere.
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.