The DMM is arguably the most versatile electrical test instrument we have. Even the most basic model can measure voltage, current, and resistance. You can use the resistance measurement function for electronics, instrumentation, controls, and many electrical applications.
For example, what’s the value of a resistance thermal device (RTD) in ohms? Your DMM will tell you, but don’t forget to zero out your test leads. Some DMMs have a test lead zeroing feature; you clip the leads together and press the button, and the meter subtracts the lead resistance from the reading.
The typical DMM runs on a 9V battery. It’s not going to measure the 480V impedance across a connection. Use an AC resistance tester (impedance tester) to read the actual impedance or use a thermographic camera to see the heat loss across it.
Become familiar with the resistance measurement limitations of your DMM, and use it for the measurements it can take. For other resistance or impedance measurements, use a different instrument.