When I had ds 1 I bought a second hand next to me crib. I bought a new mattress for it.
I was told you shouldn't use a second hand mattress. Not that I would have.
I'm now due to have dc2. I will use next to me crib again then baby will take over ds cot and ds will move into a bed.
Should I buy new mattresses again? They will technically be second hand, but only by baby's brother.