We get a new CC number when there’s one breach.I've only purchased from Newegg once--September 2018. That happened to coincidence with a 30-day time period in which their data security was breached and my credit card info was stolen. I eventually got a letter about it from Newegg, but not until after my card had been used fraudulently and had been replaced.
On the plus side, this was the only time that I've actually be able to tie down fraudulent use of one of my cards (it's happened four times on the same card) to a specific data breach.