Of course we all have our limits, but how can you possibly find your boundaries unless you explore as far and as wide as you possibly can? I would rather fail in an attempt at something new and uncharted than safely succeed in a repeat of something I have done.
Those who work at a thing heart and soul not only achieve success in it but through their absorption in that they also realize the supreme truth-Brahman. Those who work at a thing with their whole heart receive help from God.