When I started as a “home bartender,” I was hailed as one of the best bartenders my friends had ever had. My Mai Tais received special attention from friends, and I soon branched out into a wide array of other drinks which received a fair deal of praise. There was one major issue, however, that I found in my own drinks – and though my friends didn't comment on it (what with me waiting on them and everything) I'm sure they noticed. The amount of actual liquor I put in each glass was hard to balance. After all, I wasn't the sort of person who measured out everything carefully. I judged it on sight. However, bottles don't flow evenly. Pourer spuots and clickers, though, do.
Pourer spouts and clickers, both methods of getting your liquor to flow evenly and in a controlled way, were discoveries I didn't make until much later in my home bartending career. I strongly recommend getting on this investment sooner rather than later.
The advantages of pourer spouts reside in, very simply, the way they help the beverage poor. It's going to give a very even, fast flow to help you mix the drinks up more quickly and with more precision. They also prevent any dripping, which means no waste. A lot of these also come in fun styles, so it's not a bad addition to the look of your home bar, either.
If you really want precision, clickers are also available, and can be set to automatically stop flow after half an ounce, an ounce, or even more if you want, so you can mix with absolute precision very rapidly.
Resources for Drink Pourer, Bottle Pourers and Liquor Pourer