when do you stop sterilising bottles ???

♡ 𝓚𝓪𝓽𝓻𝓲𝓷𝓪 𝓵𝓸𝓾𝓲𝓼𝓮 ♡
When do you stop sterilising bottles for your baby and just go to cleaning them with washing up liquid ???  My baby is 5 months old now and has had all his injections for the time being, his next ones aren't until he's 13 months old. 
So when should i stop sterilising his bottles ????