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.
Instead of putting a paint smear across the outside of a can to mark the level of paint left inside (which can be messy and obliterate the label), use a rubber band instead. Put it around the can and roll it down to the level of the paint. Just by glancing at the rubber band, which is visible all the way around, you will know how much paint is left.