A ruler isn’t something you normally think of as evolving, but that’s just what Incra did with their precision line of rulers. Incra’s simple solution makes precision layout literally child’s play. The rulers are not only laser etched, they use a laser to cut precision holes and slots all the way through the ruler. Put the point of a sharp pencil (mechanical pencils work well, too) in the right slot or hole, and voila! Instant precision layout (unless you’re a machinist). I have the T-Rule, which I like because it also gives you a perfect right angle to work with. The T-Rule has precision slots cut in 16th and 32nd increments, and precision holes drilled every 64th of an inch.
The only downside is that Incra rulers are much thinner than ordinary rulers. Like any precision instrument, you can’t drop them or knock them around like a $4 ruler from a department store. That said, I’ve had my T-Rule for over 10 years, and it is still in perfect condition. It has its own place on a corner of my bench where it is fully supported when not in use. It’s the only ruler I have in my workshop, and I rarely work in my shop without using it at least once.