At age (nearly) 60, I look back over my lifetime and see myself as having been (and now being) two woodworkers. Thirty years ago, I accepted cutting tolerances of a 1/16 or even an 1/8 of an inch, with almost no true understanding of wood movement. Among my projects then were building two kitchens and a few standalone pieces of furniture. Today, with having had a thirty year absence from woodworking, and with an entirely new cast of tools and machinery, I have set as a goal to work towards an accuracy of 1/64 of an inch. While wood's movement itself is often greater than that tolerance, I figured I would at least shoot for that kind of accuracy even if I end up with something less fine.
Two inexpensive tools that are helping me achieve that goal are calipers (at $26.00, it gives me metric, imperial decimal, and most useful . . . fractional readings) and Lee Valley's Wood Movement Reference Guide, a wheel that helps one determine a specie's wood movement under changing temperature and humidity environments (available for $6.50 at LV).
The caliper has found a place in my apron pockets along side of the 4" starrett square. The Wood Movement Guide Wheel reminds me of the need to pay particular attention when picking through the wood pile at my local hardwoods dealer to select grain patterns most likely to expand and contract in a manner suitable to the intended design. The wood design guide wheel includes a 9-page instructional pamphlet that told me more about the nature of wood movement than any other resource.
Hey, I may never achieve my goal of 64ths, but you gotta have a target in mind, right?