Percs can definitely improve the quality of your bong rips, but they can also make your piece more difficult to clean. Resin will gunk up the nooks and crannies of the percs over time, rendering them useless.
To put it simply, a percolator is a filter inside your bong made to make bubbles. That’s right; it’s all about making bubbles! Diffusing your smoke creates bubbles which give your smoke more surface area to come into contact with the water in your piece
Tree Percs are nice and smooth. They are smoother than dome percs, and inline percs, but require more work to clean.