Measuring distance using pace/time counting is a great skill to learn and with practice you become accurate to within a few feet. A good exercise to start with is to find a big open field. Mark your starting point and take a bearing, walk a few hundred double paces, add 120 degrees and walk the same amount of paces, add a further 120 degrees and walk the same amount of paces again and you should end up exactly where you started, or at least within a few feet of it. You will have walked in a big triangle. You can do the same with adding 90 degrees to walk in a square but will need to do an extra Side (square). You could also subtract instead of adding. You can also measure your paces and time over say a kilometre of straight road and work out how long and how many paces it will take you to walk half the distance or 10 times the distance etc. It sounds complicated but if you note all your personal figures down and keep them in a notebook with your navigation equipment it's really just a matter of some simple maths to work out distances. This as has already been mentioned is very useful for night navigation or poor visability. My pace is 65 double paces = 100 metres on flat, even ground. This of course varies depending on your size or length of stride. (You have to measure it yourself). So if I'm walking along a track and I know my position, i need to turn of the track in 1,500 metres which I can measure from my map scale and compass base plate, I can relax and know I need to start looking for that exit point in about 975 paces time. The metal counting machines are excellent bits of kit and you can relax and just click on each double pace. Very accurate. You'll obviously need to adjust your figures for steep, uneven or rough terrain. Lots of people have mentioned using GPS and it definately has it's uses, especially for people involved in conservation and animal survey. I personally get a great deal of satisfaction from navigating using a map compass and associated navigation skills. They're well worth practicing.
Measure a distance on your map to a point you want to get to, and work out how many paces it will take you to get there. It's a good feeling when you get it right to within a few steps :super: