Are packages evil?

Hello,

I start with a new project and want to uses packages, but are packages evil?

What is happend when many clients use routines of the package and I want to change one (not used at the moment) and get a compile error? Are all client calls against this package fail? If yes, then I think packages are not useable in living (growing) application. :-(

What are your opinions?

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Ciao Heinz Z.