The Pension Calculator is a great tool to help you work out how much retirement income your client might receive from the amounts they save.
When you discuss what they ought to do to provide an income in retirement, investing regularly in a pension is one of their options.
If they are employed, you should first check if their employer provides a pension scheme. The employer might make a contribution that your client wouldn't get if they took out a personal pension.
If your clients don't have the option to join an employer's scheme, or are self-employed or not in employment, they could take out a personal pension, such as a stakeholder pension.