Wow, this is the first contest since a long time, nice to see that!
Small and maybe stupid question: if I enable 2FA with my mobile phone and my number changes, what to do than ?
The phone number is only used for recovery. If you lost the 2FA key you can get an SMS text message code to log in with. Go to your profile page and there is a "2FA RECOVERY DETAILS" section and you can change the number there.
Thanks TheQuin for the fast answer. I never worked before with 2FA but will activate the option soon.