Changing how we do business requires the use of new and existing tools. The grinder is a multipurpose tool. If you are young, you might even find one in mom's kitchen though I would not recommend using it for these purposes since you wouldn't want to accidently waste any of the particles left behind. She may enjoy the remnants and begin accidently leaving it lying around on purpose more often.
Grinders are used to take an "herb" and crush it into fine or small particles, depending on your taste. The end result is that they will be fairly consistent in size and shape. In as much as the same fashion as the Mortal and Pestle did, the grinding releases the herbs natural flavors and scents.
It is often said that the overall quality is enhanced but that is a misstatement. The quality is the same; it is the way that you are breaking it down that enhances it. With grinding, you are achieving a more even based and purer form of the herb than if you just chop it up and rolled it around.
Remember the days of lighting up herb and having an unfounded seed pop? With a grinder, that won't happen everything goes up in smoke. Less wasted, more tasted and another got basted. It's the way of the herb; some really just can't handle it. Keep it away from those friends who can't take it straight. If you give them something out of the grinder you may be chasing them down 5th Avenue where a 5th Avenue doesn't even exist.
With that said, there are several types and styles of grinders. For types, you can go with aluminum, copper, titanium, wood, plastic and dare I say some make their own out of who knows what. The only one that I would absolutely not recommend would be the plastic. It's too easy for it to break apart and be smoked up. It's just not natural or healthy, bad for the body you know. The wood would be the next to go on my list. It draws up the resins, and can't be cleaned up or out easily. The rest are all a matter of preference and durability.
Two Piece- includes only Top and bottom with the shell with spikes inside. This is a basic model that simply crushes your herb.
Three Piece- includes two chambers. The top chamber collects the first cuts (what you would smoke) and the pollen falls through the screen and collects in the bottom chamber. You can also store your stash in the larger bottom chamber for those long trips across town.
Four Piece-The four piece set includes all of the above with the addition of the kief collection pit. The most sought after prize, it is "said" to be the gold mine of the herb itself. The most potent and best enjoyed when sprinkled over the rest to be smoked together.
At the end of the day, your heart will find the one it likes best and you will stick with it through thick and thin. Believe me. With the grinders we have today, we can slip them in and out of our pockets in a flash if we had to. Keep one of these baby's handy; it sure would have made those applicator wrappers easier to smoke back in the day.