I must write in the greatest haste as it is already half past five and I have asked some people to come here at six for a little concert. Although I have so much to do that often I do not know whether I am on my head or my heels, I spend the whole morning giving lessons until 2 o'clock, when we have lunch ... The evening is therefore the only time I have for composing, and of that I can never be sure, as I am often asked to perform at concerts. 

Mozart to his father