A camera, microphone and cable can work separately yet fail to deliver a usable signal together. Before leaving, test the combination you will actually use on location. A packing list confirms presence. A short end-to-end test confirms that picture and sound reach the intended card and can subsequently be read in the editing workflow.
Connect the real setup
Fit the lens, tripod plate and power supply. Connect the microphone through the actual adapters and select the intended recording parameters. Speak a sentence, move something in the frame and record a short file. Play it back on headphones. This exposes a wrong input, muted transmitter or audio appearing on only one channel before the journey begins.
Transfer the file to the computer and open it in the intended software. A player displaying a clip does not always prove the editor can handle it comfortably. Check a newly selected format, high frame rate or unfamiliar memory card especially carefully. If importing is difficult, resolve the workflow now rather than after several hours of recording have created a much larger problem.
Give mechanical accessories the same attention as the main devices. The correct screw, card reader or headphone adapter can determine whether the whole setup works. Pack accessories beside the device they serve. A labelled audio pouch helps prevent similar-looking adapters being substituted without checking whether their wiring and intended function match.
Choose backup items by the failure they address
A second battery helps only if charged and compatible. An additional card helps only if it has sufficient available capacity and the device supports it. Record the condition before packing. Do not format a card until its previous files have been checked and secured. Separate free and used cards so their status remains unmistakable under time pressure.
Consider which single failure could stop the shoot. For an interview, a spare cable may matter more than another specialist lens. For extended recording, the intended external power source must work reliably. Gently test cable movement and connection stability without stressing sockets. A loose connection should not first reveal itself halfway through an important answer.
Place the packing list beside the open bags after testing and tick items as they go in. Include a return check so borrowed accessories and memory cards are not left at the location. A bench test cannot replace rehearsal in real conditions, but it removes faults that can be identified clearly before leaving home or the workspace.