What plan should I choose?
To use the app in holter mode to record ECG continuously, 24 hours a day for many days, you need the Premium plan.
If your purpose is to do workout and control your physical activity, the ideal plan would be the Plus.
If your needs are sporadic then the plan that best suits you is the Basic plan.
You should not choose a plan with a limit lower than your usage in the last month. If you want a lower plan, you must wait a few days/weeks for your monthly usage to decrease.
If you choose a plan lower than monthly usage, you will need to allow a few days/weeks for your monthly usage to decrease before you can use the benefits of your plan.