If I have boots too big, is it ok to use 2 pairs of socks?

Firstly it is always advisable to buy the right size. Thick socks or 2 pairs of cotton socks (a material that stretches and moves freely) can move around your foot, creating blisters or rubbing and less
security. For skaters whose feet are still growing, Edea recommends no more than 10mm growth room. This means by the middle of the season the skates will fit perfectly. For the early part of the season, a thicker insole can help but will reduce feel and performance slightly.