To qualify for a State Pension in the UK, you must have a national insurance contributions record with at least 10 years credits.
To qualify for a full State Pension, you must have a minimum of 35 years national insurance credits.
Many people, where they are not in paid employment or self employment at different points in their lives will therefore not be accruing credits towards their state pension. This may be because you are:
In the case of carers and homemakers, provided that you are registered as a carer or in the case of children, you are person that claims child benefit, you will still receive national insurance credits, despite not in paid employment/self employed under Home Responsibilities Protection.
Being registered unemployed also means you get national insurance credits despite not working.
Personal Tax Account
You can check on your full tax, national insurance and State Pension position today by registering with HMRC for your Personal Tax Account: https://www.gov.uk/personal-tax-account