What does the distribution of who receives welfare benefits and services and who pays the taxes that pay for them tell us about how different ways of closing the public budget deficit would affect...

What does the distribution of who receives welfare benefits and services and who pays the taxes that pay for them tell us about how different ways of closing the public budget deficit would affect different groups? Why does it matter what time period is used to measure who ‘gains’ and who ‘loses’ from welfare spending and taxation?