Answer:
-Always wipe not only the measuring faces of your tools, but of the work piece being measured as well. This will help prevent dust or dirt from marring your tools. Generally speaking, it is best not to use such tools as vernier calipers or micrometers on rough, abrasive surfaces if you can possibly avoid it.
-Always keep your tools used for measuring separate from your hand tools to save them being knocked about and damaged. Never lay your tools on something like a lathe, either, because the vibrations could compromise the accuracy of the tool.
-Always use your tools used for measuring for that alone - measuring. This means don't use your micrometers for little hammers or a vernier caliper as a line marker, for instance. This will certainly damage them.
-Always keep your tools used for measuring at or around room temperature. Never lay them on a heat source or in direct sunlight as doing so could really mess them up so that their accuracy is affected.
-Always be wary of laying or using your tools too close to a magnet or magnetized surface. Magnets can wreak havoc with many of these precision tools.
-Always clean your tools after use. Unless they're made of stainless steel, each tool should have some anti-rust oil dabbed on it and then stored by itself in a dry place.
