I think in The book Janine's baby Angela / Charlotte was a shredder. It's mentioned as something in passing.
I'm sure it also mentioned that if a handmaid had a 'good baby' she could go into a type of retirement and not have to do it again.
I seem to remember one book talking about the long term plan for handmaids. They'd expected women to choose to do it and be posted with just one family and not moved around. Their thinking was that being a wife, mother and domestic servant was too much for one woman so split the roles out. A happy household would have a wife to lead the women and be her husbands comfort, a Martha to do the housework and a handmaid to have the babies.
Econowomen wore striped uniforms in the book to show they had to be wife, Martha and handmaid.