Depending on the yarn most of my knitted stuff washes in the machine on a cool gentle wash and easily threw on the line and stretched back into shape after dry. I have tried washing smaller versions and they are fine I would actually say better after a wash.
The only thing I ask to be hand washed or dry cleaned is items from handspun wools.
I always pop a note in with simple washing instructions but it is common sense with wooolens.
My large items I sometimes pop to the laundrette as there machines are just larger and give a good wash and normally take my quilts ect at the same time once a year.
I think if you spend a couple of hundred pounds on a handmade item you do naturally take a little bit more care when cleaning.