Keeping this in view, what is the average life of flat?
50-60 years
Likewise, is living in a flat bad? Since there is less space in the flat, there is less space to fill with furniture! There are various potential cons with buying a flat: you will have more neighbours, and people tend to turnover more quickly than in houses, so you might have dream neighbours when you move in then quickly get noisy people.
Beside above, what is the life of building in India?
25-50 years
Are flats better than houses?
Why flats are awesomeUsually a bit cheaper than a house (around 65% ish of the same number of bedroomed house). Generally built in urban areas, so you can expect a decent amount of 'life' stuff going on around you. Cost of insuring the building is shared amongst the other leaseholders.