Till what age should babies take 1-2 hours nap during the day?

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.