We've done it once or twice, but now milk twice a day and rear the calf on a bucket. Doing the once a day thing is good if you only have the time to milk once a day and it does mean that if for somereason you have to be away for a whole day, it is not th end of the world as you can simply leave the calf with the cow.
Drawbacks are that the cow will probably dry off quicker, the overall milk yeild will be lower, and you may find that the cow will not let the milk down for you - she knows perfectly well you are not her calf.
It didn't work for us in the long term, but it might for you. It is a good place to start.