Instead of cutting the end of the sack and pouring mulch out like cereal, lay the bag flat, slash it the long way down the middle, then flip it over and lift the bag off. It’s the faster, easier way to handle large, heavy sacks.
If you place a layer of plastic under the mulch, be sure to apply the mulch thickly enough to block light. Most plastics degrade in the ultraviolet light of the sun. Plastic is also not permeable, so it may change the drainage in the areas where you apply it. Renew organic mulches every few years, as they break down and get spread around. You can dig old mulch into the soil and let it finish decomposing, or you can simply spread new mulch over the old.