I have been making maple syrup for about 15 years. Last year I tapped trees the 2nd week of January, and it ran all through Jan and Feb. I made about 8.5 gallons, which is a record for me. I just do it on the stove (gas). The early sap has higher concentrations of sugar, but it all makes syrup. Sugar Maples have more sugar as well. I get a gallon of syrup from about 32 - 40 gallons of sap. I do not actually boil it, as it gets overcooked when it is too hot. I just put sap into roasting pans on the stove, and add sap (with bugs and bark strained out) over and over on low heat, until it evaporates and becomes syrup. It does add a lot of moisture to my house, so I crack my scuttle hole upstairs to let the house breath.
My kids are spoiled and eat waffles and pancakes with real maple syrup 4 - 5 days/week most of the time.
I burn a pan every other year or so, and it always makes me wonder why I don't just buy the stuff - it stinks up the whole house for days.
I was thinking about tapping some trees, but I am going on vacation for a week, and wouldn't be able to watch it, so I didn't. This is the time, though.
I usually tap only large trees, and put 3 taps on the South (sunny) side of the trees - the sap runs a lot better there. Tap them about 3 - 4 feet up from the ground, 2.5 inches in, so the tap angles down a little. If you get rain water in the sap, throw it away - it will ruin syrup if you put it in.
When you get it cooked down to where you think it is done, can it in canning jars. For a twist, I put cinnamon sticks in some of my jars - 1 or 2 per jar. It tastes great. Refrigerate after opening.