If u are a trader or manufacturer in building materials u opt for composition. Benefit of composition is depends on the margin u earn vs compliance cost and also on the nature of customers u deal with i.e. registered or unregistered.
@ Manjiri., You can opt to composition scheme for based on your supplies. But, In case you ll give any Labour supplies then you can't opt to composition scheme...
In my view... Some person ll supplies labours to building works. So, I remained the option....