Your ability to make an accurate "target size" guess-ti-mate is the key to Mil-Dots. For example, if the target measures 1.5 dots and target size estimate is 30" the range is ~555 yards. If your size estimate was incorrect and the target is actually 40" the range is approximately ~740 yards. FWIW, as many variable power mil-dot scopes are only "true" mil-dots at 10x; be sure to read your manual.
I admit to becoming lazy since I could afford a laser rangefinder some 5-6 years ago. Their affordability now means that no shooter should be without one. Mil-Dots, though, offer an EMP-proof alternative. Practice is paramount. Back before I could afford a laser rangefinder, I used this regularly: Mil-Dot Master All my scopes have BDCs (I am ACOG heavy for carbines), Mil-Dots, or SPR reticules. The only exception is a Trijicon Accupoint I mounted on the SCAR-H. It has a nice hollow post with illuminated triangle. By using the height of the triangle, I have found that it makes a great BDC too. No matter what you have, get out there and learn to use it as a BDC. Even the lowly duplex was originally developed to range with and hold over.
I have one but I prefer the dots; as a Ham I prefer CW (Morse code); call me old fashioned. Wind is a huge variable and most people cannot estimate wind speed. An easy way to develop one's skill doping the wind is to purchase a weather station with an anemometer. Watch the movements of bushes, grass and trees; compare your estimate to what the anemometer reads. In time one gets right decent at it.
