It varies. Your baby will let you know when naps are no longer needed, simply by not falling asleep then anymore. Some kids go down to 1 nap daily by 1 year old, others not until 2. Some kids stop needing naps at all by 2 years, others still need it when they're school-age. Even some adults benefit from naps! whatever time your baby wakes up on his/her own from the nap is the right # of hours.
Ideally till 4-5yr. Most american children do not get enough sleep. Our lives are busy, tv/video is always on. Rather than waiting for baby to fall asleep, select a consistent naptime, preceed with quiet (reading/rocking) away from household activity and video. Inadequate sleep can be associated with more than fussiness-overeating, obesity, learning difficulties, adhd. There's a reason kindergartners take naps.