To keep my alts alive, just log in or must I undock?

[Syrus]

It hasn't deleted any of my ships yet, and I only log in and log out again.
Other people claim that's not enough though.

Some people say that buying something and selling it again will make sure the ship won't get deleted.
Others say you need to undock.
And then there are people saying you need to be online for a certain time.
Some also say a cash transfers ensure the ship doesn't get deleted.

Overall it seems like a big mystery with probably only Cannon really knowing how it works.
Because even some other admins couldn't get me a clear answer.

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