Inside, I measured distance, volume, and area, and I immediately found that this is where LDMs really shine. I also measured openings for doors and windows and took finer measurements for a kitchen replacement and installing trim. For gross measurements like square footage, each model took measurements far more accurately than necessary and much faster than a tape measure. For some finer measurements, the devices' technology showed limits. Also, I looked at processing speed to see if there were differences in how quickly the devices acquired a reliable measurement.
Square and Cubic Footage. In less time than it takes to talk about it, you can get the square or cubic footage of a room by pressing a few buttons on any of these tools. When taking a measurement from an inaccessible surface, like the ceiling in a two-story foyer or the opposite side of a wide stairwell, all the LDMs in the group worked perfectly and with the same precision.
Doors. On doors, especially big ones like French or sliding patio units, measuring from inside corner to inside corner of the framing with a tape can be awkward. Not so with LDMs. Each unit has a tailpiece that fits into one corner. Next, you aim the dot inside the opposite corner; switch corners and repeat. In about five seconds you know if the rough opening is square or not and how to adjust it. I like Hilti's tailpiece the best here because it really gets tightly into an inside corner. The tailpiece also folds outward to hook onto outside corners. For applications like this, or anywhere else you need an inside-to-inside measurement, the LDMs are a true measuring advance.
Kitchen Layout. For getting fast, accurate wall lengths, ceiling heights, and area measurements, the LDMs again worked better and faster than my tape and allowed me to work alone. But for line-to-line measurements, like between proposed layout lines for an island or for different sized appliances, the units couldn't provide a measurement because the laser had nothing on which to reflect. While the instruction manuals suggest setting up a target, pulling a tape is easier in this case.
Replacement Windows. I used the units to size replacement windows and found the tools limited. If there are jamb liners (or another jamb-to-jamb obstruction), you must measure then add that thickness to the final measurement. The same is true when measuring height: the sashes obstruct the laser.
Trim. I measured trim, hoping to find a better way to get measurements than using a helper or setting nails to hook my tape. Since I cope all my inside corners, I take all measurements from a temporary trim piece on the opposite wall. It's easy enough to fix a tape where I need it on the trim (either with a helper or with a nail), but it's more difficult to hit that point dependably with an LDM's laser dot. It's also challenging to hold the unit perfectly still and record the measurement: Pushing the "record" button can move the unit slightly, changing the result. Finally, since I'm not 18 years old anymore (or if the room is big), I can't always see if the dot is exactly on target.
Measurement Acquisition and Trustworthiness. The Hilti and Trimble acquired measurements the fastest, both taking readings quickly and reliably. The Stabila also was responsive and displayed the measurements on screen in short order. The Leica and PLS units were a bit slower to display their measurements, followed by the CST/Berger.
For getting reliable measurements, the Hilti was flawless. It was always able to get and record a good measurement; the tool never shut down, never returned a clearly erroneous measurement, and never indicated there was an error. The Trimble got good measurements about 99 percent of the time, and when something was wrong, the unit displayed a series of dashes. The other units weren't as responsive or quick to record measurements and sometimes provided a number that I knew couldn't be right. In the "sweep" mode, where I moved the unit back and forth slightly to zero in on a target, the Hilti and Spectra readouts changed constantly as I moved the units. The Stabila, CST/Berger, Leica, and PLS displays were not as sensitive to motion and sometimes didn't return consistent measurements, especially if I moved the units too quickly.