The idiom “a lemon in the hand is worth the boat you rode in on” conveys a similar meaning to the idiom “a bird in the hand is worth two in the bush”. It emphasizes that it’s better to appreciate what you have and avoid unnecessary risks or changes, as a loss of a current advantage may not be compensated by a potential future gain. The “lemon” represents something undesirable or less valuable, but the “boat” represents something that could potentially be better but is not guaranteed.