I have lived in the USA since 2005 and am in my mid 40's. I am a permanent resident of the USA, not a citizen.
While in the UK I did not contribute sufficient to NI, and so would get letters from time to time advising me to top-up.
I don't really know whether I will be living in the USA or the UK (or even somewhere else) come retirement age. I nearly have enough credits to qualify for social security in the USA.
Should I top up my NI contributions?