To 'lose the benefit'
is a phrase commonly used by mothers to forewarn their offspring
of the dangers of leaving one's overcoat/hat/gloves on once entering a heated room. ie "Take that coat off when we go inside otherwise you'll lose the benefit when we go back outside"
When one becomes a little older the phrase takes on a whole new meaning, it can either mean;
a)That you have got a job and as such are no longer entitled to income support or supplementary benefit and have 'lost the benefit'
b)That you have been unemployed for so long that the government has suspended any benefits you may have been entitled to in an attempt to stop you noding and get a job.
As one gets even older then the phrase to 'lose the benefit' can take on a slighter more sinister meaning - I am talking about the realisation that as one approaches the age of retirement (in the UK at least, I am unsure of other nations policy on such issues)that the penny pinching government you have spent the best years of your adult life paying National Insurance contributions to have decided to abolish state pensions in order to finance ludicrous projects such as the Millenium Dome (well that particular monstrosity was financed from the National Lottery slush fund, but you get my drift).