The ACA actually makes it very easy to purchase insurance only when you need it (you've moved, your employer drops your coverage), and drop it when you don't (you can go two months per year without insurance without penalty). This is a fundamental flaw in the program.

You must mandate participation through payroll taxes, but also ensure services can be affordably provided to participants. Insurance companies are still raking 20% off total premiums paid; that's money that could go directly into providing care.