Should I recommend sealing classes by default?

Question

In a big project I work for, I am considering recommending other programmers to always seal their classes if they haven\'t considered how their classes should be subclassed. Oft

Answer 1

I don't like that way to think. Java and c# are made to be OOP languages. These languages are designed in a way where a class can have a parent or a child. That's it.

Some people say that we should always start from the most restricting modifier (private, protected...) and set your member to public only when you use it externally. These people are ,to me, lazy and don't want to think about a good design at the beginning of the project.

My answer is: Design your apps in a good way now. Set your class to seal when it needs to be sealed and private when it needs to be private. Don't make them sealed by default.