You cannot manage what you do not measure. If you are going to add conditioning to your powerlifting, it helps to know where your engine actually stands and whether it is improving. You do not need a lab or a coach with a clipboard. A few simple checks tell you everything you need to know.
Watch Your Between-Set Recovery
The most useful conditioning gauge is right in your own training. Pay attention to how fast you recover between heavy sets. If you are still gasping and your heart is pounding three minutes after a hard set of squats, your engine is underbuilt. As your conditioning improves, you will notice you settle down faster and walk into your next set ready. That recovery is the conditioning that actually matters to a lifter.
A Simple Heart Rate Check
Your resting heart rate, taken first thing in the morning, is a free window into your conditioning and recovery. As your aerobic base improves, your resting rate tends to drift down over weeks. A sudden jump from your normal can also flag that you are run down and need rest. Check it now and then and watch the trend, not any single number.
A Basic Work Test
If you want a simple repeatable test, pick one. A set distance walk or row for time, or how much sled work you can do in a fixed window, then retest it every month or two under the same conditions. If the same effort gets easier or you do more in the same time, your engine is growing. Keep it simple and keep the test the same so the comparison is honest.
Watch your between-set recovery, track your resting heart rate, and run one simple work test now and then. Those checks tell you whether your conditioning is doing its job, without turning you into a numbers obsessive.