From time to time my phone will receive notification of new temporary password, An indication that my twitter account is being hacked. I thought before that it has no effect at all because the hacker cannot access my temporary password being sent to my mobile phone. True enough that the hacker have not been able to hijack my account but it was able to insert people to follow. I became follower of more that a thousand individual accounts.
One thousand two hundred sixty one to be exact. I did not remember following that  so big a number of individuals. It took me two and a half hours to unfollow them. I have retain 11 accounts to follow.The Help page have given this instructions:1. Click on Following on your homepage or profile page2. Hover over the blue Following button next to any user following list, it will change to a red unfollow3. Click the button to unfollow the account

My suggestion on how to guard your account is primarily rely on strong primary password. Do not rely on secondary password, though secondary password can help. Get a strong password containing letters, with a capital one and number, with a minimum of eight charaters.