There *is* a requirement to fly as the instructor must sign the flight(s) in your logbook to confirm the training has been given and a satisfactory standard reached.
Taildragger - expect about 5 hours
Rectractable + vp prop - exact about 2 hours
Remember if you dont fly a variant aircraft (tailwheel, vp, retractable, pressurisation, turbo/supercharged eng) for 2 years then the differences training lapses and you must get a proficiency check to revalidate the diff training.
Hope this helps