Before making measurements be sure to test your test equipment. Otherwise, you may not obtain the measurements you need or expect.
If doing acoustical measurements, calibrate your measurement microphone, with a calibrator or by using manufacturer-supplied data. If you’re using any battery-powered devices install fresh batteries, or if using rechargeables, make sure they are fully charged. Check all interconnection cables and adapters. Are they wired correctly and well-terminated?
Make sure you’re familiar with your test gear. Set up everything ahead of time and do some test measurements before you go out on a job. Test your signal generator by connecting it to your analyzer. Run through the different signals to make sure both generator and analyzer are working correctly.
Make sure analyzer range settings, if available, are appropriate for your measurements. If you have auto-ranging, test with different signal levels to make sure it’s operating properly. Many measurements can use filters, like sound pressure level or total harmonic distortion plus noise. Check the settings of these filters. Are the correct ones selected? Are the filters out when they aren’t needed?
Check the settings of other buttons, switches and dials. Be especially aware of software settings. Many appear in submenus that aren’t always in view. Make a checklist for your equipment checkout, and follow it. Keep it updated after each job. Make a list of gear and cable that you’ll definitely need and another list of what else you think you should take on a measurement job. Think spares, extra power cables, power strips, audio cable, etc.
And of course, think about what you’re trying to accomplish with your measurements, so that when you finally perform them you can check if the measurements make sense. With some jobs, you may only get one chance to get your measurements. So as with any job, preparation and planning pay off.