When me and my partner moved in together, worked out how much money we had coming in and then our outgoings (we used excel but the old fashioned pen and paper is just as good) this means we know how much money we have left after bills this usually pays for our social life, any unexpected bills or gets saved for holidays etc.
I would recommend this to anyone, as you can avoid getting into loads of debt and it also means that you can recognise any problems and deal with them. Thus making the most of your money