This just hit the news again, worth considering if you have gaps, it's not big money but looks worth it.
If you log in to your HMRC account (i use the app) it's much easier to see the NI contribution years paid, pension forecast, missing years.
https://www.birminghammail.co.uk/news/cost-of-living/martin-lewis-urges-state-pensioners-29363415
https://www.gov.uk/voluntary-national-insurance-contributions/deadlines
If i added another 4 years contributions to the max 35 years, about £3,200, over 10 years I'd receive an extra £10,400 ignoring inflation