They do become hard but not after 2-3 months. They work just fine till 20k kms and after that the noise and hardness increases. Some can live with it and some cannot .
The good thing about changing brand new tyres is that you get a good value for money for those Euros and the difference to be paid is reduced. Old Euros which are driven for 20 or 30k are worth 500- 1000 rs (all 4) or maybe nothing so it may be better to change tyres when new .
Sent from my SM-N910G using Tapatalk