Four months ago, security researchers told eBay about a way hackers could force the "forgot password" system to reset account passwords to ones hackers already knew. The only thing a hacker needed was a valid username. At the time, An Egyptian security researcher demonstrated an eBay account hack that took all of about one minute.
Given that hackers had usernames for 120+ million eBay users thanks to the previous hack, this was a serious problem. If that wasn't scary enough, eBay took four months to roll out a fix.
That means for the last four months, your account has been vulnerable to hackers - and the repeated password changes from other hacks only made it worse.
Well, eBay has finally fixed the problem, so it's a good idea to reset your password again just to be safe.
Given how often you're being asked to change your password, it might be a good time to look at password manager software that can create strong new passwords for you. KeePass is a good place to start. Otherwise, make sure you follow my system for creating a strong, easy-to-remember password.