Would you sell if there were no tax implications?

When people say something is a "strong hold at this price", why don't they sell?

I am particularly talking about people who have most of their portfolios in tax advantaged accounts like ISA and IRA. If that's not you, take this is a hypothetical question.

Surely if something in you portfolio is a "hold" you should just sell it and buy something that you currently consider a "buy" IF there are no tax implications. Would YOU sell if there were no tax implications?