How should I strategize/make plan on buying new things and preloved stuffs? I'm sure both kinds will give me different value. What is actually worth to be bought new -not only because of safety and hygiene factor- and what's not?

i also had experience bought preloved for my baby atleast its can save money and many of PL things still good quality.I little worry before about hygine and safety but before use i make sure to clean again all and as long as use PL things over all its ok