in my limited experience...
yes, depending on your goat!
I work full time, but my husband is around in the day. He often doesnt milk until I'm home, the goat just isnt ready early on, and has a good belly full of hay then eats her concentrates or chews the cud during milking (she is too awkward otherwise)
Neither our current milker or her predecesor have been huge volume milkers - if you have a super milker then she would need more regular milking to be comfortable.
when the weather is bad (too wet, too hot, too cold) Geraldine has refused to stand to be milked, and will go "full" overnight to give far more the following day (we tell by the size of her udders - sometimes it just isnt there!)
you really need to consider whether your goats will be safe to be left all day without getting into mischief, or escaping, or running out of water etc. ours have the benefit of if they shout loud enough, somebody comes out to check them!
if you are organised, with eg buckets, clean equipment, storage etc ready the night before, it doesnt actually take that long to milk so you may be able to milk before you go to work, then do the pasteurising later on.
again, my experience is very short... but as for your question on lenght of lactaction -
Margo came to us in May, she stayed in milk til about Christmas, but then she was ill and died not long after.
Geraldine kidded at the end of July and has really ceased now, we get a little every couple of days. She should be back in kid soon if not already as she runs with the billy.
As I said she is soon affected by the weather, so after snow, minus 18 temps and now all day fog, she is quite fed up!
She peeps out the doorway, deciding whether what's in it for her before she comes outside!
hope that helps, somebody much more knowledgeable will be along soon (I've got too much time in my hands while I'm in holiday

)