These can be applicable in USA and most of developed countries.
1 If a citizen or permanent resident have paid tax more amount, and have paid tax more years and month, and have relative good credit history, so the citizen or permanent resident can be got pension beforehand (earlier than 65 years old), and can be got more amount of pension.
2 If a citizen or permanent resident have never paid tax, or have paid a few tax in before, so the person can't be got any welfare. Will prohibit any person to get something for nothing.
3 If a citizen or permanent resident under 40 years of age, usually can't be got most of welfare.