About ten minutes each for the cupboards, Foxy. Maybe a little bit longer for plasterboard. The trouble is, it takes longer to drive there and get all the tools etc from the van than actually doing the job.
Allow for two hours.......... assuming various inevitable problems though.
Rates vary a great deal.
A good tip, if you ever get a handyman/builder in............ make a list of a few other jobs too. Try and make up at least a morning's work. He'll get a lot more done - hence cheaper in the long run.