To return to the OP!
I would say is that the best thing to do is to relax into your knew-gained wealth. (grin)
Next time you are in the supermarket and see a delectable you really fancy, do not turn your head and walk by, indulge yourself. next time you wash a well-worn pair of trousers and decide that they need to last another year, chuck em out, and buy a new pair - and better quality - they will last even longer. .
As others say, unless your wealth is immense, in which case this extra income is immaterial, put some of it by - for holidays, car repairs and to replace whit goods and the occasional private out patients appointment.
After that, just relax into your new income - you will be surprised how soon expenditure meets income!