Similar word to wellspent:

abounding, abundant, advantageous, beneficial, blooming, blossoming, breeding, childing, conducive, copious, effective, fecund, fertile, flourishing, flush, fructiferous, gainful, plenteous, plentiful, profitable, profuse, proliferant, prolific, propagating, reproducing, rewarding, rich, spawning, successful, useful, well-spent, worthwhile