To easily and quickly break up meat in the skillet while browning it, don't trouble yourself with trying to mash it with a wooden spoon. What a hassle and it never breaks it all up uniformly. You have some pieces that are small, some that are large, what a pain.
Instead, break out your potato masher!
Mush it down on the meats as you're cooking and watch how fast they break up into perfect uniform size - so fast and easy ... give it try next time you're browning ground meat or sausage in a skillet.