when should one give up?

Never give up! If you believe in your idea - don't listen to anyone and go forward! (No one is saying that an idea can't change over time - that's fine, but never, do you hear me? NEVER stop believing in yourself!)

What the comments say, just pivot.

This is the hardest part of an entrepreneur's life; when to push on and and when to surrender. Let's put aside for a sec the "never surrender" mottos and separate two things (your idea and yourself) - never give up on yourself - learn from our ideas that don't work! Making mistakes is how we learn, how we grow. Making mistakes is human, choosing to learn from them is the only thing we can actually control in this whole crazy process.

Deciding to pivot or persevere in entrepreneurship is like debugging code: sometimes you need to tweak the algorithm before hitting that sweet spot!