If you are working on a project with a partner and using two different measuring tapes, take the time to check that both tapes are in synch. Sometimes if the hook end of an older tape happens to get bent, it may throw off the measurement as much as a sixteenth of an inch. That error can be enough to cause problems if you need to do precision work. To doublecheck two metal measuring tapes for accuracy, mark a line at a certain distance on a board, draw the tapes out and compare readings.
Look at the Climate Region Map on the Energy Star label to be sure that the window, door, or skylight you have selected is appropriate for where you live.