Inactive accounts are usually deleted after a certain time, although this is not a definite rule. Like I have an account on Youtube, which I haven't visited for more than two years --- and which I can't reach, because I lost my e-mail to which it was bound, due to ownership changes among operators.
All I can say is, use different usernames and create your passwords with something like
Random Password Generator, Safe Password Generator and Manager - IObit.
It'll be much safer than the name of your pet, or eq. There's no way you can dispose of your trails in Internet, thus you need to ascertain it in advance. Use as many symbols and letters as you can.